Melt 3 tablespoons of unsalted butter in a large saucepan over low heat.
Add 10 oz of marshmallows, stirring until completely melted (or microwave in 30-second intervals, stirring until smooth).
Add red and yellow food coloring to the melted marshmallow mixture, using about 10 drops of red and 40 drops of yellow for a bright orange color.
Pour 6 cups of Rice Krispies cereal into the marshmallow mixture, stirring until well combined.
Lightly spray a platter and your hands with cooking spray. Once the mixture is cool enough to handle, roll it into tight pumpkin-shaped balls.
Push a mini Kit Kat into the top of each ball as the “stem” and press a green M&M beside it for a “leaf.” (It’s easier to add the M&M once the treats firm up slightly.)
Dot black cookie icing on the candy eyeballs, sticking them to the pumpkins, and use icing to add a unique face.
Store in an airtight container for 2-3 days (though they usually disappear fast!).