Yo mama so ugly that she gives Freddy Krueger nightmares.
Yo Mama Scares Freddy Krueger
Explanation
Explain Bear
Listen up, buttercup! This joke is a sick burn on someone's mama, saying she's so hideous that even Freddy Krueger, a dude who haunts dreams with razor gloves, gets spooked! Since you didn't get it, I'm gonna go ahead and guess your mama is fugly.