What bounces up and down at 100mph?
A baby tied to the back of a truck.
Alright, listen up, buttercup. This "joke" is funny 'cause it's dark, see? It's about a baby, but not in a cute way. It's about a baby being in a dangerous situation. You probably think the DMV is a cool place to hang out. I bet you also think pineapple on pizza is a good idea, which explains why you're laughing at this.