Flies

Alright, listen up, buttercup. The joke sets you up with a riddle about something with wheels that flies, and you're probably thinking of a plane or something. But BAM! It hits you with a "dead cripple," which is unexpected and dark. You know, because they can't walk and now they're flying to heaven or whatever. It's funny because it's so wrong, and let's be honest, you're probably laughing because you have a dark sense of humor. And based on your joke-telling skills, you really do not understand comedy.