Happy Halloween! Go out and get some candy! If you can't trick-or-treat for it, maybe it's on clearance in a store?
I don't remember if they did a Pokémon episode where they trick-or-treated. But they have Ghost types, and a lot of those have truly horrible stories involving them. For example, that one in the front is called a Phantump, and according to old tales, Phantumps are stumps possessed by the spirits of children who died while lost in the forest. Yeah. I copied that word-for-word from the game's pokedex. Yikes.