In a small pot melt the butter. Add the mini-marshmallows. Stir to coat the marshmallows with the butter. Continue stirring until the marshmallows are completely melted.
Pour the melted marshmallows over the popcorn. Stir to coat all of the popcorn with the marshmallow mix.
Sprinkle with the candy corn, M&Ms, and sprinkles and serve.