The Grim Adventures of Billy & Mandy - Season 1 Episode 17 -

Billy, Mandy, and Grim go to the museum on a school trip. There, they meet Hoss Delgado, self-appointed hunter of the paranormal, who upon spotting Grim, tries to eliminate him. Subsequently, Grim and Delgado engage in a fight. Finally, Delgado quits hunting Grim when he realizes Billy and Mandy control him. In the end, Delgado continues his adventures and is seen fighting a werewolf.