Boogeyman is one of Yin and Yang's friends. Boogeyman is a disco-loving green monster, and has a funky speech that's hard for anyone to understand. Not much is known about Boogeyman, as he's only appeared in a couple of episodes to which he was significant in.
When Yin and Yang were having issues deciding on how to defeat Pondscüm, Zarnot, Fastidious and Mastermind in "Roboticus Maximus", they recruited Boogeyman as a sidekick that they could boss around. However, when they still couldn't decide on what to do successfully (even with an egg-timer), they let Boogeyman take charge, and he lead them to victory. He became part of the Woo-Foo army they've gathered since then, with Roger Jr., Lina, Coop and Jobeaux also being recruited. He is currently A Woo Foo Knight in a Little Less Training.