Measure the Kellogg’s® Rice Krispies® cereal into a very large bowl, and set aside.

Place the marshmallows and butter in a large microwave-safe bowl. Microwave on high in 30 second intervals, stirring after each interval, until mixture is totally melted and fully incorporated. Immediately pour the mixture over the cereal, stirring to combine. Dump the mixture into a greased 9x13x2" pan, pressing evenly. Cool for 30 minutes, or until completely set.

Invert the pan onto a cutting board. Using the skull cookie cutter, cut out as many skulls as possible from the prepared Kellogg’s® Rice Krispies® treats. (My 3" cutter yielded exactly 12 skulls.)

Melt the candy melts according to the package instructions, adding 2-3 tablespoons of shortening to the melted candy to achieve a thin enough consistency for dipping. Dip each of the skull shapes into the candy coating, using a small spatula to smooth the coating evenly, if necessary. Reserve any unused candy coating, and keep warm and melted. Place the skull treats on a cookie sheet lined with wax paper and refrigerate for 15-20 minutes, until the candy coating is completely set.

When the coating is set, it's time for the fun part--turning these plain skulls into festive Day of the Dead sugar skulls!

To do so, use a small frosting spatula to spread a thin layer of the candy coating onto the top of one of the treats. While the coating is still wet (you need to work quickly!), add assorted embellishments as desired. I opted to add rainbow nonpareils and flower sprinkles on the top portion of the skulls, before adding peppermint candy eyes, two sugar pearls for a nose, a row of white Tic-Tac teeth, and jumbo sprinkles and flower sprinkles for cheeks, and then finishing everything off with some piped frosting accents: small purple stars at the top, large green star eyes topped with flower sprinkles, small purple stars on the cheeks, and a black frosting smile to bring it all together!