Well shit, I didn't expect this one to be so hard!
Clue 7: This enemy was meant to appear in a canceled game, and was eventually reused in another one.
Clue 7a: There is only one in the entire game.
Clue 7b: It was created for Phoenix's Rayman 4.
Clue 7c: It has a moustache.
Clue 7d: It appears in Rayman Raving Rabbids for the GBA.
Clue 7e: It appears in the Child world.