Mortal Kombat vs. David Bowie
Okay, bear with me on this one. This sort of standard universe tossery happens and the Mortal Kombat crew invade the real world, but when Shang Tsung attempts to pilfer the soul of David Bowie, it fractures into every single identity the popular singer has ever had. And so the roster is filled with such characters as the Thin White Duke, Aladdin Sane, Ziggy Stardust and Major Tom. The final battle would of course be against Jareth the Goblin King, whose alarmingly prominent crotch bulge is is simultaneously his weak spot and his special attack.