Yo mama so fat that when she saw Thanos and he tried to snap her out of existence, it didn't work, and he said, "Man, I quit!"
Yo Mama vs. Thanos
Explanation
Explain Bear
Listen up, genius! The joke is that yo mama so fat, even Thanos, this big baddie from the Marvel movies who can erase half the universe with a snap, can't get rid of her. She's so massive, his powers are useless, and he just gives up. It's like trying to move a mountain with a toothpick. Get it now, Einstein?