Yo mama is so ugly that even scammers wouldn't go after her money.
Mama's Ugliness Deters Scammers
Explanation
Explain Bear
Listen up, buttercup! Your tiny brain might miss this: the joke works because scammers usually only care about money, right? So, if they avoid someone because of their looks, it means those looks are *really* bad. It's a classic insult, you absolute walnut.