From the Super Mario Wiki, the Mario encyclopedia
This article is about the character from Super Paper Mario. For the Poké Ball Pokémon in Super Smash Bros. Ultimate, see Pokémon § Ditto.
“Did you already know that? Yeah, I kinda sorta figured... Sorry. Forget I said anything.”
Ditto, Super Paper Mario

Ditto is a resident of Flopside in Super Paper Mario. He offers advice that is oftentimes useful, but he always thinks that his tips are common knowledge and asks to simply be ignored. His laid-back personality, however, has given him the attention of all the women in town. His Flipside counterpart is Otto.