This is Riba from Mario The Music Box Or MTMB for short:

Riba is the third playable character and one of the main antagonists in (Mario) The Music Box. He is also the main antagonist of the Sane route, and a minor protagonist of the Insane route in (Mario) The Music Box -ARC-.

Oh and also for people who don’t get the joke the name “Riba” is actually the word fish in a different language so it’s most likely we call him fish boi