Spread the cereal onto a large rimmed baking sheet, then pick out all the marshmallows. Set marshmallows aside, and place cereal in a large bowl.
Heat the candy melts according to package directions. Pour over cereal and stir to coat. Spread out onto a wax paper covered baking sheet. Sprinkle with Halloween sprinkles and let dry.
Once dry, sprinkle marshmallows back into the mix.