Crossovers That Should Happen Just Because of a Random Thing on the Internet!
The Mighty Thor vs. The World's Mightiest Mortal, Captain Marvel!
This drawing is by Rags Morales, who I think drew this for an issue of Wizard. (And yes, I know they already fought in DC vs. Marvel, but that series sucked and the fight lasted four pages and Thor was wearing his worst costume ever, so indulge me, okay?)
All right, so how does this go down? Well, it can only involve a case of mistaken identity!
Loki, the god of mischief, decides to make some trouble by teleporting Black Adam right into the middle of a celebration that involves Balder, Sif, and the Warriors Three. With the element of surprise and also just because the story calls for it, Adam's able to take down the guys and escapes, leaving Lady Sif alone to chase him.
Thor gets to the scene of the battle soon afterward and asks the Warriors Three what happened, and all Volstagg could do is describe the assailant as an incredibly strong flying man with a lightning bolt on his chest. Just in time, Captain Marvel, sent by the wizard Shazam, shows up in Asgard, and Thor mistakes him for the one who's attacked his friends.
The battle is joined!
Thor gets in a few hits for a while, but Cap's got the strength of Hercules, and he's able to withstand it, and finally he hits back. They go back and forth, exchanging blows, and then Cap tries to call the magic lightning down on Thor, yelling "Shazam!" and then getting out of the way so the lightning hits Thor...
...but Thor is the God of Thunder, and by the power of mighty Mjolnir, he deflects the magic lightning and aims it right at Captain Marvel, who, knowing it would transform him back to puny Billy Batson, gets out of the way. But as he's ducking, Thor throws Mjolnir right at him...
...which Captain Marvel then catches, stunning Thor. Cap swings the hammer at Thor, but Thor blocks Cap's swing, realizing that if Cap is worthy to hold Mjolnir, he can't be the one he's after. The two of them exchange stories, and that's when Loki and Black Adam show up.