Well, I'm pretty sure there were instances where Mario and Bowser cooperated. But it doesn't matter, because even if only 2 answers make sense, the joke already works.
General rules:
Exceptions may be made at the discretion of the mods.
Well, I'm pretty sure there were instances where Mario and Bowser cooperated. But it doesn't matter, because even if only 2 answers make sense, the joke already works.