Waiter: That’s not a fly, it’s a little piece of potato.
Waiter: No, it’s a cockroach.
Customer: Well what's it doing in my soup?
Waiter: the backstroke.
Waiter: No, it's giving birth. See the millions of tiny cockroaches pouring out of the egg sac on the end of its abdomen?
[the waiter and customer stare at the baby cockroaches swimming around]
Customer: Look, I hate to seem rude, but . . .
Waiter: Let me guess: you'd like a new bowl.
Customer: No, I'd like you to take a bath. You smell awful.
ADVANCED JOKE-TELLING ADVICE: When you get to the part where the baby cockroaches crawl out, do a little cockroach dance, and maybe pretend the baby cockroaches are tickling the person you're telling the joke to. Perhaps they're even crawling down the person's shirt collar and into their pants? Your call.