My question to you all is which Marvel supervillian could take Superman in a fight. Now ignore this prep $#!+ the scenario is this: Superman accidentally flies through a subtle rift in the DCU and ends up in the Marvel Universe, completely unaware he has done so. Whilst flying along he is attacked by your Marvel bad guy. Why? This is how super fights start usually randomly because good guy stumbles across bad guy and bad guy lashes out resulting in fight. Now this isn't to the death or other retarded conditions. It's Superman from when YOU know him best.
And this is the Marvel universe SO: there's no kryptonite here, adamantium is the strongest metal around, there's no Fortress of Solitude but the Sun is yellow.
So which Marvel bad guy could take down the Man of Steel? And maybe a why as well not just "Juggernaut stomps lol"