The Grim Adventures of Billy and Mandy - 3x24 - Five O'Clock Shadows- Followmy.tv

Grim is annoyed by Billy who thinks that a shadow is following him. Subsequently, Grim takes Billy and Mandy to the Shadows' World, where their opposites live. Grim tells them to do whatever they want, but to be back at 5 o'clock, when the portal to the normal world opens. Grim also warns Billy about the door to other dimensions, but Billy opens it and a multitude of Billys come out an wreak havoc.