add the marshmallows, cook over low/medium heat until the marshmallows are ALMOST melted, they'll still be a little lumpy
spray a bowl with non stick spray, add the cereal
Pour it over the cereal and stir it, well (spray your spatula with non stick spray too)
Add any mix in's and stir again
pour into a 9x13 pan and pat down (spray your pan and hands with non stick spray as well)
let cool and cut into squares, or cut out with pumpkin shaped cookie cutters
Video
Notes
Most seasonal marshmallows are sold at target and/or walmart, but you can find them in your area using this finder https://www.kraftrecipes.com/products/productlocator.aspx