Tonton Streaming Ghostbusters (1986) S1E51 - Little Big Bat

When Prime Evil learns that Belfry wants to be bigger he disguises himself as the magician Monroe and hands him an amulet to help him. When Belfry shows the amulet to the Ghostbusters it shoots out a beam, shrinking them. Belfry must learn a valuable lesson as he helps Jessica and Futura save the Ghostbusters.