Combine the butter and marshmallows in a large bowl and microwave for 2-3 minutes until contents are soft and melty. Spray a spoon with cooking spray and stir until thoroughly mixed. Add the pumpkin puree and pumpkin pie spice and stir together until thoroughly mixed. Add the rice krispies and stir until the cereal is completely coated. Let the mixture stand to cool for about 10 minutes. This cooling step is necessary for the mixture to be formed into balls.

Separate the mixture into 20 even piles on a sheet of parchment paper. Mist the palms of your hands and your fingers with cooking spray (to prevent sticking) and press and roll each pile into a round ball about 2” in diameter. Press a pretzel third into the top of each ball and eat the little leftover pretzel third.