It is an NON-OFFICIAL NINTENDO character (we still wait, sign the petition)

Bowsette, as the internet has named her, is a character merge inspired by the idea of Bowser using the Super Crown to transform into a Peach version. She appears to have originated from the work of artist aykk92 on Twitter, who sketched an amusing comic strip imagining a spurned Mario and Bowser finding love using the Super Crown...Change

Ph: J7 Pro