In the episode, Mr. Bumpy is disguised as Molly Coddle and is playing a prank on a love sick Destructo. Bumpy makes Destructo chase him and hides at the top of the shelf, then Bumpy drops a large heavy Sumo Wrestler on Destructo.
He is squashed by the Sumo Wrestler, the wrestler gets up and says "Hai, Arigato" (yes, thank you) and walks away. Bumpy then laughs hysterically and says that sumo wrestlers "come in handy" and that he "never leaves home without one."
The Sumo Wrestler appears again in the episode "It Came from the Closet and wouldn't leave", Bumpy is trying to keep the Closet Monster from breaking into his home, so he uses the Sumo Wrestler to hold the door shut. The Sumo Wrestler is only there in one scene and isn't shown again for the rest of the episode.