As Chief of the Wizards' Council
Muldoon attempted to define all magical creatures as either a Being or a Beast, on the simple premise that any member of the magical community that walked on two legs were Beings, and all others were Beasts. However, when he called the first meeting of all Beings to discuss new magical laws, the summit was disrupted by Diricawls, Augureys, Fwoopers, Pixies and Fairies who could not understand what was going on, Trolls who proceeded to smash apart the meeting chamber with their clubs and hags who glided around the place in search of children to eat. Muldoon, as Chief of the Council, stood up to open the meeting, but slipped on Porlock dung and ran cursing from the hall.
- Muldoon is an Irish family name. It is an anglicisation of the Irish Ó Maoldúin, "descended from Maoldúin," which in turn was a legendary first name. This name means "king or chieftain of the fort". They were said to be of royal birth and styled themselves as the Kings of Lurg, which is now in County Fermanagh. Famous politicians with that surname include Sir Robert Muldoon (1921–1992), a Prime Minister of New Zealand; and Bristow Muldoon (b. 1964), a former Scottish Labour politician.
- Harry Potter and the Philosopher's Stone (video game) (Appears on a Famous Wizard Card)
- Harry Potter and the Chamber of Secrets (video game) (Appears on a Famous Wizard Card)
- Harry Potter and the Prisoner of Azkaban (video game) (Appears on a Famous Wizard Card)
- Fantastic Beasts and Where to Find Them
- Harry Potter: Hogwarts Mystery (Mentioned only)