Yo mama is so fat, she got locked in a weapon store, and she broke it down without any weapons.
Yo Mama Too Fat
Explanation
Explain Bear
Listen up, buttercup. This "yo mama" joke is all about exaggerating how fat someone's mom is. The joke says yo mama is so fat that when she got stuck in a weapon store, she broke it down without using any weapons, because she's just that big. See? It's funny because it's ridiculous!