Degenerate

by Matt Casamassina, Mateusz Michalski (Illustrator)

Mason Kowalski, a twenty-four year-old copywriter for a San Mateo startup, is on the verge of a nervous breakdown when he inexplicably suffers widespread vision loss in one eye. The doctors say it’s macular degeneration triggered by overwhelming stress, but he wonders if it’s something more, especially when the shadows in his peripheral vision begin to take shape and whisper wonderful and horrible things to him. Is it madness or destiny? The answer could destroy everything and everyone he holds dear.

Journey into the absurd beating heart of Silicon Valley as Mason and his lovable friends scramble to stop a demented serial killer from murdering more children. Degenerate mashes horror and sci-fi into a twisted, dark, violent and funny pulp drowned in tentacled nightmares. Featuring infamous hijacker DB Cooper and more twists than you can imagine, the genre-breaking story is designed for fans of Stephen King, Blake Crouch, Peter Clines, Keith Rosson, Chuck Wendig and John Scalzi.

Genres: Horror

428 pages, Kindle Edition

Published November 19, 2025

About the author

Matt Casamassina is a video game / technology journalist, executive, and author who cofounded IGN.com and built Apple's App Store games editorial team. He's written three books, Dead Weight, Sophistication, and Degenerate, and is hard at work on his fourth. Matt is married, has three kids, two dogs, and a fat cat, and lives in northern California.

For more timely updates, visit Matt’s website at www.mattcasa.com

Reviews

[Alenna Burleson · Rating 4 out of 5]

In this story we follow Mason, Mason struggles with mental health with his anxiety’s and the stresses of taking care of his almost non verbal grandmother he has a lot of his plate. When a sudden pain in his eye and his boss getting on him leads to the death of his boss and a brand new set of symptoms that would confuse anyone.

This was such a wild journey, if you are into sci- fi horror this one is definitely for you. The characters were all working so well together between the banter and the way they got along.

This story seems like it’s going one way and then it takes you into a different universe quite literally. I did enjoy the way it went but there were some parts that felt confusing for the plot. Overall it cleared itself up and ended very well.

Thank you Netgalley for sending this over.

[ellie · Rating 2 out of 5]

thank you netgallery for this copy.

I unfortunately couldn't finish this book.
doesn't make it bad, it's not a bad read at all, it just wasn't for me. the idea was really interesting and I was excited to read this and see how it would all play out, but I felt like the execution had some flaws, the story felt dragged at times because of the slow pacing and unnecessary scenes. just couldn't keep me engaged enough.

[Mars Azel · Rating 4 out of 5]

Degenerate is a satirical rollercoaster of cosmic horror with a wild superhero twist. Much like a comic book this story hits the gas on page one and never lets up. It's violent, gory, and relentlessly paced, expertly balancing high-stakes action with dark, cynical laughs.

[Draculise A. · Rating 4 out of 5]

If stories about monsters once stayed in the shadows, Degenerate reveals what happens when the shadow steps forward wearing the face of someone you loved. This novel is not about clean heroism or chosen destiny. It is about inheritance, fear, and the slow ruin that begins when the mind you trust becomes an unreliable witness. Matt Casamassina crafts a world where memory frays, where voices slide under your skin, and where the past does not stay buried. It follows Mason Kowalski, a man already stretched thin, who discovers the darkness inside him is not a metaphor. It is alive. It speaks. And it wants control.

The unraveling begins with a firing that twists into possession, a boss laughing through a fog of shadows that Mason cannot explain. It spreads to interrogation rooms where officers convulse and lose their minds, to a suited stranger who dissolves into blackness, leaving only his laughter behind. From there the horror widens: mutilated children, stolen memories, a grandfather whose tenderness once felt like salvation now revealed as something older, crueler, and monstrously transformed. Mason is pushed from the city into impossible landscapes, from wheat fields watched by colossal hawks to underground tiers governed by myth and fear. Reality bends. Worlds collide. And through it all, the danger remains intimate, as if every nightmare began at his family’s dinner table.

What anchors the story is desperation. Mason runs through silent corridors hunted by the possessed. He faces the truth that his powers may save him or consume him. He watches friends stand beside him even when the world unravels into cosmic ruin. And he learns that love, loyalty, even memory can lie.

A Glimpse into the Degeneration:

A man hunted by his own mind.
A grandfather reborn as a monster.
A world built on myth, collapse, and quiet terror.
Violence that strips away the boundary between human and nightmare.
A reality that fractures until it almost disappears.

If you want a story that whispers its horror, that sinks rather than shocks, Degenerate will not comfort you. But it will remain.

[Bookish Burnished Bee · Rating 5 out of 5]

I don’t know how to describe the vibe of this novel. It starts with a harsh, realistic look at life and the struggles of anxiety and mental health. Tendrils of something unnatural start to wave in and out. A warm, wide and inclusive cast of characters is introduced. It’s a comfortable read, with enough intrigue to keep you turning each page.

And then the energy shoots off into grotesque, almost cosmic horror vibes. And then you find yourself ignoring your usual bedtime because how are you supposed to put this down now?

I loved the real, perfectly imperfect characters. I loved to see Mason’s personality tease out when he’s amongst people that has his back, as opposed to the bitter, nihilistic working man just trying to survive the hellscape of daily life. The author writes with charisma, sarcasm and sass — but in a natural way that doesn’t feel contrived or overdone. The dark humour tucked into various scenes feels authentic— I can totally see feeling the same way in those situations.

—-

I received an advance review copy for free, and I am leaving this review voluntarily.

[Hitesh Thakar]

⭐ Degenerate – Review

Rating: 4/5

Degenerate is one of those books that hits you with intensity right from the opening chapter. What surprised me most wasn’t the action or thriller elements, but how emotionally grounded the story felt. The characters are written in a way that makes their anxiety, stress, and paranoia feel uncomfortably real — especially Mason. I found myself reacting strongly to his internal struggles, because the writing makes you feel the pressure building inside him in a way that’s almost claustrophobic.

The book blends psychological tension with surreal, almost nightmarish moments. Some scenes made me pause because I wasn’t sure if what I was seeing through the character’s eyes was real or part of his mental unraveling — and honestly, that uncertainty is what kept me turning the pages. It creates a sense of unease that stays with you even after you stop reading.

Emotionally, I found myself frustrated for the characters, angry at the situations they are put into, and curious about what was actually happening beneath the surface. That emotional engagement is where the book shines brightest.

If I had to offer constructive criticism, I’d say a few transitions felt slightly rushed. Some intense scenes hit extremely hard, but the cooldown moments could’ve used a bit more space for reflection — especially since the main character’s mental state is such a big part of the story. A little more breathing room between the chaos would have made the emotional punches land even harder.

Still, the writing is sharp, the pacing mostly strong, and the blend of psychological horror and human drama feels unique. If you enjoy stories that blur the line between reality and hallucination, and characters who feel painfully human, this book will definitely pull you in.

[The Nocturnal Reader · Rating 5 out of 5]

If you asked me where this plot was going, I would have been wrong. If I was starting to get an idea, something would happen, and I'd be back at square one!
This book just kept getting weirder as things started happening. It takes a lot to gross me out, but there were several moments that I gagged. I did a double take when a character I thought didn't really matter suddenly mattered a lot. And somehow, in the epilog section, I was shocked again by something out of left field showed up.
I wasn't sure if I truly cared for Mason as the main character, but he grew on me just as everyone else did. I also was a little sad that the ending was as clean as it was. I really wanted to be some kind of consequence for all the bad the characters went through. However, the last epilog made me ok with its clean bow.
I'll be thinking about this book for a while simply due to the twists that punched you in the brain.

[Laura · Rating 2 out of 5]

Let’s jump straight into it—Casamassina knows how to write.
But so does 87% of the world's population aged 15 and up. Does he know how to write clearly and engagingly? ‘Cause I do need a new favorite author. We’re about to find out. (Well, I'm about to find out; you can probably judge the rating already)

The book Degenerate (still not certain whether a noun or a verb) starts with infamous DB Cooper holding a plane hostage.
Alright, so I’ll start this off by saying I have a teensy bit of background in aviation, and while the chapter reads fairly okay, this is where I tripped up (I have receipts!):

“[..] because they aren’t allowed to fly any faster than 115 mph or higher than 10k feet.”

If we’re talking a commercial airliner, 115 mph, depending on tonnage, is a stall. As in “brace for impact in 3..2..1”. Unless the author meant knots, which, generally, is preferred in aviation, but still would be too low a speed. Are we talking a Boeing 727 or similar? Granted, there’s DB Cooper in the chapter. Otherwise, the airplane chapter reads fine. Although—confused about the era of that flight. This could prove a problem for people who don’t know who DB Cooper was, and that the plane “borrowing” happened in 1971. So, timestamps would’ve made it easier to follow it all. (Also, a fuselage includes the cockpit as well as wiring and insulation, among other things. It’s the frame of the plane minus the wings, engines, etc—that’s a note for the author.)

Next. Characters. Oh boy. I will make a generalized statement right now, but—men have an odd way of writing women. Portrayal of Cassy/Cassandra (and later Yinny) is problematic. I can, with certainty, say I have never in my life met a woman who speaks the way she does. Starting with “Hey yo, it’s me—coming in. Hope ya’ll mu’fuckas be decent,” to “What, ya’ll think your gran ain’t heard this shit before? Bitch, she was circling blocks before your dumb ass was swimmin’ up into life.” She is described as a husky Samoan with broad shoulders and hair pulled into cornrows. Then called a hulk. Then claiming she outweighs the main character by at least 75lbs. Probably should’ve gone through a round of sensitivity readers with this one(female ones). That being said—she was fun to read and was a good supporting character to the protagonist. So, I guess we pick our battles.

On to Mace/Mason.
I’ll put this right at the start of this section, to get it quickly out of the way—When did Mason start recording the conversation with the Prick(love the name)? Feels very Deus Ex, which is bizarre because that’s literally the second chapter. But maybe I just missed the detail. Aaaaand—nope. I checked. No mention of any recording being set up. Just that Mason has somehow been recording a conversation with his boss, which, we later come to know, holds something else.
Furthermore, Mason reads like… wet cardboard. I’ll leave it at that.

The prose, although clean and engaging, is filled with errors, some of which I will list below:

Referring to a CT scan:
“Lots of deep bass noises and crazy hammering.”
Is factually incorrect. The author confused an MRI with a CT scan. MRI is the banging noise, CT is more of a quiet whirr.

“She’s coherent.” Is wild to say about a grandmother who only ever says one word—hungry/Hungary.

"and now it rots behind a weeded field just as neglected" < “weeded” is not the correct word to use. “Weeded” means we removed the weeds, which then means—a field that has been carefully cleared of weeds, yet somehow neglected? Hmm.

"Train tracks cut San Mateo in half, on one side the invasive super rich and their shielded high-tech bubble world, on the other the persistent natives, their *rundown, dirty lives* not just ignored but pushed farther and farther back until there’s no space left for them." While I get what the author was trying to relay in theory, the phrasing is… peculiar. I will leave it at that. And knock one star off for it.

“Their rays search for [..]” Guess what this is about. Flashlights. Confused? You and I both.

And a few sentences later: “There's a rickety staircase that must've ascended to an attic.” STAIRCASES DON’T ASCEND!

“My name is Steve Willis, staff sergeant, San Mateo Police.” Within the US—and I think San Mateo is well within the bounds of the US—a staff sergeant is a military rank. This is generally how it goes:

Staff Sergeant → U.S. Army / Marines / Air Force / Space Force
Police (U.S.) → Officer → Sergeant → Lieutenant → Captain → etc.
Now, within the UK, yes. There are staff sergeants (although rarely used as a rank).

“He blinks, rubs his eyes, and tries to push away the ethereal nature of reality as seen through the lens of exhaustion." At this point, I’m pissed, and the kindle flies across the room. ‘Cause what does that even mean? Ethereal nature of reality… what?

“Sir, if we do not see you at the department or hear from you presently, we will dispatch units to detain you for questioning. Do not ignore our attempts to reach you.” That’s not how it works. In the US, police cannot detain someone for questioning just because they don’t respond. In the US:
a) You have no legal obligation to answer police calls.

b) You have no obligation to come to the station voluntarily.

c) Silence or non-response is not probable cause.

d) “Questioning” alone is not grounds for detention.
Police need reasonable suspicion (for a stop) or probable cause (for arrest).

In short, the author probably knows the denotation of a word but not the connotation. A tip: if you’re looking up a fancier word to substitute for the one you know via Thesaurus—check the full meaning and how the word is used in a sentence.

Conclusion: Degenerate by Matt Casamassina made me feel like my brain was degenerating whilst reading it, hence I did not finish it. Clocked out at 30%. While the story may’ve been interesting as a concept, the execution kept pulling me out of it constantly, and I don’t believe the story past the 30% mark is any more finetuned than it is up to it.


ARC read.

[Jude Samson]

The writer doesn’t know what kind of book he’s writing and it shows. This was tough to get through between the glaring issues that pop up regularly and the story itself being all over the place.

Negotiable dollars? Lol what?

The end of a lot cigarette is always glowing not just when one inhales.

Lol since when do planes use mph? And also 115mph? They’d drop out of the sky

How does Vaseline on a tinted window make anything darker? What a ridiculous analogy

Again with these ridiculously stupid metaphors - spun around paranoid man with a severe tick? Is he spin around a lot or twitching? otherwise he’s not ticking and how is spinning around equated with paranoia?

Head cold into the Ebola virus? Soooooo lol the man flu.

And then randomly mentioning Ebola again while hearing the “did you call me boy” monster voice playback on the phone. What’s his obsession with Ebola?

Is this a doctor or a surfer dude?

Macular degeneration doesn’t “clear up” when stress is removed. It can be triggered or worsened by stress but it is a “degenerative” condition and will only get worse, not better or cured.

CT scans don’t make much noise and they are often very quick so he wouldn’t feel too claustrophobic unless he’s pretty prone to it in general. The MRI is loud and banging and takes a lot longer to complete the imagining. Think of a CT like a scanner - quick and quiet, and an MRI like a printer - longer with much more back and forth of the arm and noisier.

Holy cow how many times is this dude going to waste page space reiterating his mantra. We get it already.

Who calls a phone an iPhone? Most people will just say “where’s your phone”

Why wouldn’t he record the conversation after the threats and treatment he got before? California protects CONFIDENTIAL conversations. The one prick had was in public and thus not covered under the two party consent terms. Also, also, mason didn’t threaten him in a court of law, he threatened him with using the recording to HR.

The voice of Siri is not manufactured. It’s a real person’s voice.

Bushy isn’t going to give details about the murders? lol it’s 2019 there’d be information about everything aspect of it all over the news or social media regardless of if the police try to keep it hush.

If bushy isn’t talking then how does mason suddenly know the bodies were mutilated?

Lol the cops can try to dispatch a unit but there’s no obligation for anyone to speak to the police. Also, we aren’t really given a time frame of the others other than deducing that the blueser apparently called three times within an hour and that’s a bit excessive to jump right to threats (which are empty).

Staff Sargent? Did we enter a military zone? And even if he meant just a regular Sargent why is he calling and not a detective?

If the cops had a ton of evidence or any cause they wouldn’t have called him to come down they would’ve gotten a warrant and arrested him.

“Like a fisherman can feel the tug of a hooked tuna” lol I’m sorry what? How is this supposed to indicate some kind of “knowing” or “other sense” when ANYONE even a first timer kid can feel when they’ve hooked a fish. It’s a literal tug.

Police having to disclose their police if directly asked is a very old myth

A patrolman wouldn’t be that aggressive or threatening with warrants. And why don’t Rudy come out of the bedroom?

Lol is the dude from the lodge Irish or a pirate?

Not putting incriminating details of murders in a diary is hardly proof of innocence much less undeniable.

The door at the police station doesn’t slide ajar - ajar means a slight opening and sliding isn’t even right either. He pushes it open. Keep us simple and accurate.

Mason can’t seem to draw in enough AIR not oxygen. We don’t breathe pure oxygen, it would kill us.

Omg stop with the bullet point list of every single sign on the door. We all know what the typical signage is and the list doesn’t provide anything to the story except annoyance.

The writer randomly uses bigger or more official words when smaller more commonly used ones are just fine. A good example is when Rudy says the guy could’ve died of influenza. No one ever calls it influenza, they just say flu.

Did the writer really think we had to have “simulated” explained to us?

Cassie is so tiring and mason has zero sense of urgency no matter what’s happening.

I highly doubt mason is feeling sleepy as he’s plummeting on a free fall. Sleep and consciousness are not the same thing.

His mouth was as dry as a German Shepard? Lol wtf is that even supposed to mean?

Continuing the story to a conclusion is not an epilogue. The epilogue is a recap or explaination about the conclusion. Him waking up in after his free fall is part of the ending not an epilogue. And writers need to stop doing epilogues like they’re standard for every book. It’s bad enough to have one but this joker has THREE

[sam · Rating 4 out of 5]

Mason is a stressed-out copywriter in San Mateo with anxiety, vision problems, and a life that’s very much spiraling. Doctors say it’s stress. Reality says… maybe not. Soon he’s seeing shadows take shape, reality starts glitching, and things go fully off the rails—like his boss literally shoving termination papers up his butt (yes, that happens), or an entire police station collectively forgetting he’s a murder suspect. Toss in his ride-or-die, foul-mouthed bestie Cassy, his conspiracy-obsessed friend Rudy, and a very real guy named DB Cooper who Mason catches spying on him (because of course), and suddenly he’s knee-deep in something much bigger, darker, and weirder than burnout.

This book is an absolute fever dream in the best way. It starts off feeling like cosmic horror, veers into murder mystery territory, and then fully faceplants into wild sci-fi insanity with simulations, asteroids, and good old tentacle-y nightmare fuel. I genuinely never knew where it was going next, and that unpredictability was half the fun. It’s chaotic, unhinged, funny, and bizarrely thoughtful—one of those reads where you just shrug and go, sure, why not, and let it take you wherever it wants. Weird, entertaining, and delightfully degenerate.

[Hugh Binns · Rating 5 out of 5]

Loved it. I’ve read all of Matt Casamassina’s novels and Degenerate is, without question, his strongest and most ambitious work so far. It’s a genuinely original story with an epic feel, packed with vivid characters, sharp dialogue and a plot that refuses to sit comfortably in any single genre.

What sets this book apart is its insight into the darker, more corrosive side of Silicon Valley–style ambition. Rather than leaping straight into full dystopian sci-fi, the novel lingers in that unsettling space just before everything tips over — and it’s all the more effective for it. The world Casamassina builds feels disturbingly close to our own, which gives the story real weight as it grows stranger and more intense.

There are moments of outrageous humour, sudden turns that completely wrong-foot you, and passages that are surprisingly thoughtful and lyrical. Casamassina takes real risks here, but they pay off, resulting in a novel that’s gripping, unpredictable and often downright insane in the best possible way.

This is a bold, genre-bending thriller that stays with you long after you’ve finished. Hugely enjoyable in print, and the audiobook is equally compelling. Highly recommended.

[George Stull · Rating 4 out of 5]

Think Stranger Things only with DB Cooper, a former Navy Seal, and a couple of best friends just trying to live their lives. A unique blend of horror, mystery and sci-fi. The characters are loveable, something that is very difficult to pull off in a novel like this. How often can a book scare you, make you laugh and even bring a tear to your eye? This one can do all of that along with a captivating story that will make you want to keep turning pages. To quote directly from the book "I guess times flies when you be chillin' with shadow monsters and looking for serial killers and stuff." You'll be flipping pages right up to the out of this world ending. I heard this book was a mix of Stephen King, Blake Crouch and Chuck Wendig and I could not agree more. If you like any of those authors, this book is for you!

[Ellie W · Rating 4 out of 5]

WOW, this book was such a wild ride! The plot is a total mash-up that starts as a horror & then halfway through it flips into a full sci-fi. I don’t think I’ve ever seen anything like it, but it grew on me as I got closer to the end of the story.

The “Blurry Man” had some body-horror-esque moments which I found to be quite enjoyable, even humorous at times. Pretty equally plot- & dialogue-driven as a story too, especially as more characters and weird scenarios were introduced. Imagery was glorious both in the “human” world & “space”; the author does a great job building the different scenes & setting the tone in both halves of the story.

I would definitely read this book again & would recommend it to fans of comic books honestly, it kind of reads the same!

Thank you so much to NetGalley for sending me an advance copy of this book!

[Reading Xennial · Rating 4 out of 5]

This was unhinged in the best way possible. I was surprised many, many times. There were parts I had to reread because I was so blindsided by the events. It is quite gross at times so that’s something to be aware of. This book is not for the faint of heart. Even through the twisty events, the plot was still good and the characters were fun to read. I’ve never read from Casamassina before, but I will look into his previous works. This is a book I will be thinking of for quite some time. I highly recommend this book.

Thank you, NetGalley and Matt Casamassina for allowing me to read this early. The opinion in this review is my own.

[Rich Rosell · Rating 3 out of 5]

This is a truly bizarro novel, something I imagine would be a complimentary description to the author. Because - well, it is. Bizarro, that is. A young copywriter develops a mysterious affliction that seems to cause horrific, mind-melting hallucinations. And then the dead bodies start piling up. Oh, and then D.B. Cooper shows up, decades and decades after his infamous jump out of a plane.

I wasn't necessarily in love with where this went story-wise, but I can honestly say it was NOT anything I could have anticipated.

I really liked the main characters, and Casamassina handles dialogue extremely well, full of punchy sarcasm and humor.

I would read more from this author......

[Trisha T · Rating 2 out of 5]

I struggled to finish this book. It felt scattered and unfocused, with multiple plots rolled into one. What began as a horror story suddenly took a sharp turn into sci-fi. While I enjoy both genres, the abrupt shift made the overall plot feel clunky and disjointed. There were also several plot holes that seemed to be filled with “just because” explanations. That said, I really enjoyed the main character, Mason, and appreciated his development throughout the story. I can’t help but think that if this had been split into two separate books, I might have enjoyed each story much more.

Thank you Netgalley for this ARC in exchange for my unbiased review.

[Travis Butler · Rating 4 out of 5]

Degenerate
By Matt Casamassina

Mason is having eye pain that leads to hallucinations and fainting. When he comes to crazy things have happened. Children have gone missing. Copper, a man who should have been dead for many years, has shown up to help Mason and his friends solve the mystery of what is happening to and around him.
This book is an absolute mind fuck. One of the craziest books I have ever read and I loved it.
Thank you to NetGalley and the author for the he opportunity to read this book early in return for my honest review.

[Mickie Gray · Rating 4 out of 5]

Loved This!!

I started reading this book thinking it was a thriller/horror story, but halfway thru it took a complete left turn. It turned into a story I never thought would interest me.....but, I couldn't put it down. I was so fascinated I had to know how it ended.
If you want something different, you must read this book! I could imagine each character in real life. I laughed at times and scratched my head at others.
One of the best books I've read in a long time!

[Emziethebookworm · Rating 4 out of 5]

I didn't know what a was walking in on as soon as a started to read this book as I thought it was gonna be smooth sailing but wow wasn't I wrong.
It was certainly a book that knows how to draw in it's audience readers, a mean the plot was really amazing to me.
The characters were good throughout the book, however didn't like one but that's fine.
Thank you to netgallery for allowing me to read this book.

[Danielle Heptinstall · Rating 5 out of 5]

I am in absolutely awe with how the book ended, my jaw literally hit the floor! The way the story begans, definitely has no indication of how it will end. You will be taken on an absolutely fever dream of a ride! I was laughing, I was gasping, I was on the edge of my seat! I would love to read a sequel!

*I was given this ARC in exchange for an honest review *

[dnrizm · Rating 2 out of 5]

I think I would describe Degenarate a quirky buddy cop cosmic horror romp. There was the odd couple and some cosmic horror. I don't think I followed the thread, to be honest. There were points where I was having fun and others when I was scratching my head. By the end of the story, I was kind of wondering how we'd gotten where we were.

Definitely try it if you like odd couple type cosmic romps.

[Kate Hergott · Rating 4 out of 5]

Degenerate is a mind bending, satirical journey through a horror tinged Silicon Valley. It's perfect for fans of Dark Matter by Black Crouch, Dead Money by Jason Kerr and The Matrix. I really enjoyed this unique take on a thriller in Silicon Valley, and how Casamassina blended horror elements into somewhat speculative fiction.

Come to figure out what's wrong with Mason's vision, stay for the quippy remarks and very lovable cast of characters.