Wings of Fire discussion

I think Animus dragons are SOOOOO cool. I think what they should all do first is to enchant themselves to be immortal, have infinite power, not be able to be wounded, be able to be invisible, and all those things that would make them invincible. I wonder why Turtle doesn't just enchant the armband he already wears around all the time and everywhere with all of his spells. That is, can you enchant something over and over?