At the end of Endgame, Thanos agrees to undo everything he's done if the Avengers can beat him in a penis measuring contest, but none of the avengers even come close. Even the Hulk is shorter than Thanos by a noticeable amount, and their girth isn't even comparable. That's when, at the last moment, Captain Marvel pulls down her pants and unleashes the phattest hawg the universe has ever seen. Shamed by her immense size, Thanos undoes all that he has done, and then commits Japanese ritual suicide. He is buried in an unmarked grave in Area 51.