If you're using store-bought rice krispies treat unwrap them. Then skewer each treat with a lollipop stick pressing it into the short end of the treat until it's about halfway in.
Line 2 baking sheets with parchment paper or a silicone baking mat or lay the parchment paper out on the counter. (see note) Pour each color of sprinkles into its own separate bowl. Set the bowls next to the parchment paper workspace.
Pour the candy melts into microwave-safe bowls, adding only one color to each bowl. Place one candy melts bowl in the microwave and cook on high for 30 seconds, remove, and stir. Continue to microwave in 15-second increments, removing each time to stir before heating for another 15 seconds. Repeat until all the wafers are completely melted. (You'll only work with one color of candy melts at a time to make sure the coating stays melted. Repeat these steps for additional colors when each set is finished.)
Once melted place the candy melts next to the sprinkles bowl. Then dip a rice krispie treat into the melted candy so that about 2/3 of the treat is coated. Hold the treat upside down by the stick and let most of the excess candy drip back into the bowl, for about 5 seconds. (When you get low on candy melts you can use a spoon to help cover the treats.)
After dipping in the chocolate, dip the top of the treat into the same color sprinkles. Then lay the treat down on the parchment paper. While the coating is still soft, carefully place the eyes. You can make some monsters into cyclopes, and others can have multiple eyes. Repeat with the remaining treats.
Let the coating sit for about 10-15 minutes to dry and harden. Once set, store the treats in an airtight container or resealable zipper bag at room temperature. For best taste, eat within 3-4 days.
Notes
Nutritional information is based on using store-bought Rice Krispies Treats.
You will need space to decorate all 20 treats at the same time or you will have to work in batches, letting each batch set completely before moving on.