Why can't you make fun of a bunny's head?
Because they have a hare-line.
Bunny's Hairline
Explanation
Explain Bear
Okay, so get this, you dummy. It's a play on words. "Hare-line" sounds like "hairline," which is where your hair starts on your forehead. Bunnies are hares, get it? You probably don't since you're reading this explanation, bozo.