A friend of mine passed on this link from Quizlaw.com about a dentist who played a practical joke on his assistant and was sued for it.
"Meanwhile, the far more entertaining story today involves a dentist who thought it would be hilarious to stick some phony pig’s tusks in his assistant’s mouth while she was under anesthesia. He took the tusks out before his assistant woke up, but he took pictures, which eventually circulated around the office and were given to the assistant during her office birthday party. So, his assistant — who clearly has absolutely no sense of humor — quit her job and sued the dentist."
Check it out to see how the story ends!