In Mark's one episode, he and his sister were going to see the dentist, Frank Graves whom he doesn't want to go see. When he saw how excited Emily was about going, he told her that their parents and Dr. Graves had decided to pull all her teeth out, and she couldn't say anything to their parents that she knows; otherwise she could go to the hospital.
Mark's plan worked until Dr. Graves uncovered the joke and pulled a return joke on Mark with the help of Emily that taught him a valuable lesson about not hurting those we love with mean, practical jokes.
- See Forbes family
|“|| Mark Forbes: <sarcastically> What’s the magic word?
Jean Forbes: Go!
Mark Forbes: Well, that works too.
|“|| Jean Forbes: Go tell her to get in here!
Mark Forbes: What's the magic word?
Jean Forbes: GO!!
Mark Forbes: Well, that works, too.