Beau is a character that appears in the episode "Thanks for the Crabapples, Giuseppe." He rides the bus with Ice King, Abracadaniel, Ron James, Ancient Sleeping Magi of Life Giving, Little Dude, Leaf Man, Giuseppe, and the Nymphs to Big Butt Rock. He does not do or say much on the trip, though he appears to get along with Ice King, as they are seen playing rock-paper-scissors in the background, and is shown enjoying Leaf Man's poem. He is presumably part of the secret society the wizards formed at the end of the episode.
He (or a wizard that looks just like him) also appears on the title card for "Wizards Only, Fools."
He has blue skin, a conical gray hat, and a long-sleeved brown shirt.