Mario's archnemesis and the reason Peach spends more time in "another castle" than in her own. His plans almost never work out, and occasionally he even finds himself on Mario's side. In Smash Bros., he's a serious heavyweight who laughs off weaker attacks. Hit him hard to send him flying!
Bowser makes good use of his heavy physique with his down special Bowser Bomb, slamming down with his backside. If he's on the ground, he'll jump into the air before crashing down. Also, he can gain a bit of altitude if you press the special button repeatedly while executing his up special Whirling Fortress.