Bubo is a vile little creature that has appeared in numerous episodes of The Trap Door. A prankster and a bully, this wretched little thing has a nasty habit of climbing out of the Trap Door purely to annoy Berk and his friends. When he first appeared in the episode "Gourmet's Delight", Bubo was invisible. However, after Berk threw a glob of yellow scunge at him, he has since appeared as a short yellow creature with a perpetual frown and a strange tube on top of his head. It's not clear what this orifice is for, but Berk once used it to inflate Bubo like a balloon and then let him go whizzing around the castle until he went plummeting down the trap door again.
One of Bubo's favourite things is throwing scunge (slime) at folks. In his last appearance, he got into a scunge fight with Berk and Rog which ended when Rog slapped him back down the trap door with his oversized hand.