>>37080507This.
As soon as I saw Y form I decided Mewtwo was inspired from dbz villains. I mean why wouldn't it be considering db and dbz were the most popular shonen anime in the late 80s and early 90s before pokemon. It could be a coincidence, it's really just sharing the same colour scheme and a tail. The colours green and purple are commonly associated with alien like creatures.
This is sort of like in Hunter X Hunter, Meruem is quite obviously inspired by cell. It's almost an exact rip off.