Grease or spray a 9x13 glass baking dish. (If using a metal baking sheet, I like to line it with parchment paper.) Over medium heat, melt the butter in a large pot. Add the marshmallows to the pot and stir until melted. Add in the rice krispie cereal and stir until the cereal is fully mixed with the marshmallows.

Transfer the rice krispie mixture into the 9x13 dish and press down until the top is flat. Allow the rice krispie treats to set for 30 minutes.

Remove the rice krispie treats from the baking dish and cut into 12 even sized rectangles.

Melt the green and black candy melts according to the package. It can be done in a double boiler or microwave. Dip the top of each rice krispie treat into the melted green candy.

Next dip the top of the green part of the treat into the sprinkles to make it look like hair.

Add two candy eyeballs for the eyes then use the black icing to draw a crooked mouth that looks like stitches. Allow to set fully before serving or transferring to an airtight container. To store arrange in a single layer then use wax paper or parchment paper before topping with another layer of treats.