There's gonna be 8 planets right after I destroy Uranus.
Destroy Uranus
Categories
Explanation
Experiment
Explain Bear
Hey, dummy! The joke is a pun. "Your anus" sounds like "Uranus", which is a planet. The joke implies the speaker is going to destroy the listener's butt, and that will leave only 8 planets in the solar system. Get it now, bonehead?