Mr. Duppy was a picture of humpty dumpty that Adam had hanging on his wall when he was little. It was scary, and he frequently told his mom to remove it. Because he couldn't pronounce Humpty Dumpty, he called it "Mr. Duppy." Mr. Duppy is frequently drawn as an egg-shaped character that is wearing boots. Although he is rarely referred to by his first name, sometimes he is called "Jim Duppy", because it sounds funny.
The boys made an effort to include Mr. Duppy everywhere. Whenever Adam came over to Liam's House , he drew Mr. Duppy on the kitchen whiteboard with the phrase "DUPPY LIVES." This became a symbol that has since graced many whiteboards.
Mr. Duppy was also called emare dup.
When Liam registers a program on his computer, he always registers it to the company The Duppy Clan.