Dimentio

Dimentio is the main antagonist of Super Paper Mario and has shown to be self-aware during the game.

Super Paper Mario
During the 5th world, Dimentio hypnotises O'Chunks using a floral sprout. He says right before the player fights him "Now remember kids: eat your vegetables to grow big!" "Except in this case, a veggie will eat YOU! have fun, now!