Ok it's these kids that go trick or treating, and they're all one color. A witch turns them into their halloween costumes. I remember one turns into frankenstein. Then they go to a party where the parents are at and they scare them. The kids start getting sad because they think they have to stay as what they've become. The witch turns good at the end. It's an animated movie, probably on the disney channel, but it's not disney.

Witch's night out