Montalk

“In reality things are more complicated since any single alien faction can have multiple purposes, but the point is that negative ones basically seek to use us, positive ones seek to help us. The most common alien types are the grays, reptilians, mantids and nordics.* Grays are short robotic beings with large heads, pale skin, and dark eyes. Reptilians are tall intelligent beings with slit pupils and scaly skin. Mantids look like man-sized praying mantises. Nordics are indistinguishable from humans but tend to be more muscular with exclusively blond hair and light colored eyes.”
― Montalk, Fringe Knowledge for Beginners