Ernie the Pest is a ghost and boss from Jack the Reaper. He is the ghost of a serial killer named Bernard Gorelli, who was sent to the electric chair. In Toshiko Crash-Up, he appears in the Museum stage.
Ernie the Pest appears in the Museum stage. Before the mash-up, he will occasionally crawl along the stage's walls and ceiling, damaging any opponent he touches. Sometime during the match, Ernie will leave the stage and Benjamin Ethal will walk into the background of the stage, seemingly watching the players fight. Eventually, Ernie sneaks up behind Ethal and devours him whole.