In a bowl, beat butter, powdered sugar, milk, vanilla extract, and violet food coloring on slow speed, gradually increasing to high, until smooth, fluffy and evenly tinted.
Frost each cupcake generously.
In a microwave-safe bowl, combine green candy melts, white candy melts and 1 teaspoon of coconut oil in the microwave at 30-second intervals, stirring in between, until smooth and completely melted.
Cut cereal treats in half and dip each into the melted candy to fully coat. Carefully place in a single layer on a parchment-lined baking sheet.
Place 2 eyes on each coated cereal treat and 2 licorice pieces on the side to resemble Frankenstein’s monster’s bolt. Allow to set.
In a microwave-safe bowl, combine brown candy melts and 1 teaspoon of coconut oil in the microwave at 30-second intervals, stirring in between, until smooth and completely melted.
Dip the top part of the coated cereal treat to resemble Frankenstein’s hair. Carefully place back on the baking sheet and allow to set.
Using the black frosting, draw eyebrows and a smile to complete face. Carefully place each decorated cereal treat on top of each cupcake.