What's brown and sticky? A stick with poop on it.
Or a stick with poo on it.
Brown and Sticky
Explanation
Explain Bear
Listen up, buttercup. The joke is a play on words. You expect something complicated, but it's just a stick covered in poop. It's funny because it's so simple and gross. It's like when you try to understand quantum physics, but you can't. You dumb.