What makes Mahito dangerous isn't his ability to transform himself, but rather his ability to mutilate/ murder others like Shigaraki, Scar, Killer Queen and Kimbee.
Mahito: JJK scarry femboy who has the ability to shapeshift himself and others.
Shigaraki: MHA hands guy. The artist is really a hands on guy.
Scar: FMA brown dude with tribal tattoo on his right arm and obviously, big scar on his face.
Killer Queen: JJBA P4 cat ghost guardian of a guy who likes hands too much. 33 yo, always 3rd place but will beat yo arse if necessary.
Kimbee: FMA guy who likes bombs. Basically he is domestic terrorist.