In a large mixing bowl, combine the popcorn, pretzels, and mini marshmallows.
Melt your chocolate according to the directions on the back of the package. Pour the chocolate over the popcorn mix and stir to combine.
Stir in half of the Reese's, candy corn and pumpkins, and sprinkles.
Pour the mixture out onto the sheet pan and top it with the remaining Reese's, candy corn and pumpkins, and sprinkles. Allow the chocolate to set, about 15 minutes.
When it sets, break it apart into bite-size pieces.