Bowser's laugh is like this: "Bwa ha ha ha ha ha!" or like this: "Gwa ha ha ha ha!" They're both basically the same thing...
Wario's laugh is like this: "Ah heh heh heh heh heh heh!"
Yoshi's laugh is like this: "Yo-yo-yo-yo-yoshi!"
Mario's laugh is like this: "Ah, ha ha ha ha ha ha ha!"
Toad's laugh is like this: "Eee eee eee eee eee eee!"
Peach's laugh is like this: "He he he he he he he he he!"
Get the point? Videogame character's all basically laugh the same way!
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"Bwa ha ha! Guess who it is, loyal Mario fans...
It is I, King Bowser... ruler of all Koopas, big and small. I have come to take over the Mushroom Kingdom (no, not the place...I mean the WEB SITE!)! Deezer, you will surrender your troops to me, or else you will never see your precious Mario again! Bwa ha ha ha ha ha ha ha ha ha!"