Hawking's Final Ride

Alright listen up buttercup. This joke is funny because Stephen Hawking, a famous scientist, died, and the joke says he got hit by a "Universal Serial Bus," which sounds like a regular bus but is also a computer thingy, see? It's a pun, and puns are like the training wheels of comedy for people who still think farts are the peak of humor. You probably laugh at those too, don't you?