Japanese game maker Suda 51 (Killer 7, No More Heroes, Let It Die) has an idea for a Mario game, and it's as weird as his other games. When asked what he would do if he had control of the franchise, Suda pitched the following:
"So this really bad guy's captured Luigi, so Mario and Koopa (Bowser) become friends and they go together...It's like a road movie in a car. So they go from the south to the north and just go through it, like through America. I think it'd be great to make a Mario game like that."
Surprisingly, the idea isn't over the top violent or riddled in mystery, so maybe this is an honest pitch! Suda did say he would "probably" tone down the blood, but I'm sure he would jump at the opportunity to develop a Mario title for Nintendo. The chances of that happening are incredibly low, but never say never!
A Bowser and Mario team up isn't unprecedented. The two joined forces in Super Mario RPG to dethrone Smitty from the Mushroom Kingdom and again in Superstar Saga. I would love to see how Suda 51 captures the two's dynamic though! I'll just bury that because I know it ain't ever happening...