Place aluminum foil in a 9x13 pan and grease lightly.
Melt butter in a large pot over medium heat.
Add 8 cups of mini marshmallows and stir with a wooden spoon until the marshmallows are just melted (about 3-4 minutes)
Add Rice Krispie cereal to mix and stir to combine.
Add in last 2 cups of mini marshmallows and stir.
Stir in 1/2 tsp of blue sprinkles & 1/2 tsp purple sprinkles and stir to combine for Sulley. (For Mike Stir in 1/2 tsp green sprinkles & 1/2 tsp candy eyes)
Add remaining blue and purple sprinkles for Sulley and pour into prepared pan. (For Mike use remaining green sprinkles and candy eyes)
Sprinkle a few more blue and purple sprinkles on top for Sulley; green sprinkles and candy eyes for Mike.