Stephanie something or the other (never read about her in the comics till her death, she was better of as the Spoiler)
Thanos is virtually a god. He's destroyed he Marvel Universe and recreated it...he is near undefeatable and there is no major comic bock hero that he hasn't wiped he floor with....he's has, however, lost to a lesser known mutant by the name of Squirrel Girl...whose mutant power.... is the ability to, not psychicly, but actually...talk to f**king squirrels. She's also beaten Dr Doom and Deadpool among others.
how the hell did squirrel girl beat them?
Squirrel Girl carries a utility belt comprised of multiple pouches which contain nuts to give as snacks to her squirrel friends. These are known, to much comedic effect, as her "nut sacks".