In my opinion the end-all confrontation between Mario and Sonic happened back in
Smash Bros. Brawl, and giving both mascots the ability to bludgeon, fry, zap, detonate and hurl each other into a hellish abyss was enough. Apparently it wasn't enough for Sega, because they stuck them in the Olympic Games of all places. It's been know for a while they're making a sequel to their original mascot competing minigame collection:
Mario and Sonic at the Winter Olympic Games, and here's the first media.
I thought the first game was a pretty silly idea but it sold through the roof and into an adjacent solar system, so the chilly weather followup was inevitable. They've released the first official gameplay trailer, but I still think it's patently ridiculous. Really--Mario with even the slimmest chance of besting Sonic in
any speed-related competition? Simply impossible.