Yo mama is so fat that when she fell, I didn't laugh, but the sidewalk cracked up.
Yo Mama So Fat She Cracked the Sidewalk Up
Explanation
Explain Bear
Listen up, orphinkid0444444dadnevercameback, you absolute buffoon. This joke plays on the classic "Yo Mama" format, but with a twist. Instead of you laughing at yo mama's fall, it's the sidewalk that cracks up, implying she's so fat that her weight damages concrete. Get it? Probably not.