The Grim Adventures of Billy and Mandy (2001)

S1E16 Hoss Delgado: Spectral Exterminator

During a school outing to the museum, Billy, Mandy, and Grim encounter Hoss Delgado, a self-declared expert on supernatural creatures. Mistaking Grim for a ghost, Hoss attempts to capture him, leading to a showdown between the two. The confrontation takes a turn when Hoss discovers that Billy and Mandy actually have control over Grim. Recognizing this, he decides to abandon his pursuit of Grim. The episode concludes with Hoss continuing his thrilling escapades, now battling a fearsome werewolf.