Andy 28!
Goomba
I think is Super Mario Galaxy, he really took seriously his plan without joking and you can see how powerful is when he is decided to defeat Mario, the cinematic of the UFO is absolute cinema, probably the best Bowser battle in the main games, and he isn't fine only with defeat Mario and kidnap Peach, he's DESTROYING THE UNIVERSE so the battle feels like if Bowser wins is the end of the world, also in Bowser's Fury he has one of the best appearances and he only wants destroy Mario and nothing more cares about even his Son, but I don't think that is his best appearance but if you think that I totally understand why. Also in Bowser's Inside Story has a really good retreating of Bowser and the same goes for Brothership.