In a medium sauce pan melt butter and peanut butter over medium heat for 3 minutes stirring with a wooden spoon. Add marshmallows and food coloring. Continue to stir until marshmallows are melted and sticky like glue. A wooden spoon is important here because the mixture will stick less to this surface.
Remove from heat and stir in Rice Krispie cereal. Blend well.
Although I highly recommend wearing powder-free latex gloves, you can also use wax paper to mold the warm mixture into round balls.
Push a tootsie roll into the top for the stem. The heat from the pumpkin will create a malleable material so the tootsie roll can be gently bent. Ridges in the tootsie roll create a natural and woody effect.
Allow pumpkins to cool completely, then decorate with frosting.