The Omnitrix 2.0 allows the user to turn into 50 aliens at the start but after Ion tampered with it it gave access to 100 aliens here are the main aliens Steel Wheel(Cannonbolt) Brainy(Greymatter) Hugalion Eon Chronian X(after sampling Isies) Lanoes Froth(Big Chill like but no legs) Splixor(not Ditto) ????????(the only alien never used on it) Spike These aliens were used on both sides good and evil. the only reason the ???????? was never used is because Ion warned them that one use from that monster would destroy the user,the galaxy he/she is in and create a black hole that would destroy that half of the universe.