Over the Garden Wall/YMMV

Complete Monster: The Beast is the appropriately named evil entity that dwells in the forests of The Unknown. He lures victims and sings to them, convincing them to let despair take them over and die, so that they could turn into Edelwood trees. The oil within the trees is their souls and he uses them to keep the flame of his lantern, which houses his own soul, lit to live. While it may seem he's attempting to survive, his actions make it clear it's out of a desire to live on to claim more victims. He fools the Woodsman into thinking he murdered his daughter and trapped her soul in the lantern so that he'd chop the trees and grind them for him while he moves on to find more victims. He takes interest in Greg and Wirt and stalks them throughout the mini-series. When Wirt falls into despair, Greg offers to take his place. The Beast makes Greg do pointless tasks that he says will help them get home when in fact they are meant to exhaust him so he'd freeze to death. At the end, he makes the same deal to Wirt as he did to the Woodsman, clearly lying because he knows Greg will die and Wirt will spend the rest of his life as the Beast's pawn. An unfeeling demon who views all around him as pawns and food, the Beast cements himself as the most vile creature in Cartoon Network's first mini-series.