Dakota Fanning vs DC Earth!
Dakota Fanning has learned that the existence of DC Earth has prevented her performances from getting recognition from the Academy. They also caused her teeth.
She decides to obliterate all of non-bulletproof DC Earth as retribution.
Dakota gets 2000 years prep on Marvel Earth. She receives the comprehensive knowledge of Marvel Earth, equivalent of a Marvel solo series character, as well as basic (public) knowledge of DC characters. She doesn't age during her prep. She is then transported to DC Earth to enact her divine justice.
How many non-bulletproof heroes or villains can she kill before her rampage is stopped? If she can even be stopped at all!
Now I know what you're thinking, Dakota doesn't stand a chance in hell right? Wrong!!!
Bear in mind a regular boy learned magic enough to take on X-Factor. Dakota is a really really clever girl, despite her unfortunate dentition, she has all those long lines and all and she has two whole millennia! She's also really pissed, re:teeth, see picture above. This is Dakota as you've never seen her before, the gloves are officially off.
Dakota Fanning:
http://en.wikipedia.org/wiki/Dakota_Fanning
DC Comics:
http://en.wikipedia.org/wiki/DC_Comics
Round 2: If Dakota is somehow killed or stopped (although this is highly unlikely) she gets a second chance, with help from her good friend Mugen Tom Hanks.