Melt the unsalted butter in a large saucepan over low heat.

Once the butter is fully melted, add in the mini marshmallows and stir continuously until they are completely melted and combined with the butter.

If you want to give your brains a creepy color, mix in a few drops of pink or red food coloring and stir until evenly distributed.

Remove the saucepan from the heat and gradually fold in the Rice Krispies cereal. Mix gently until all the cereal is coated in the marshmallow mixture.

Grease your hands with butter to prevent sticking, and shape the mixture into small brain-like forms, pressing into a brain-shaped mold for uniformity.

Place the brains on a baking sheet lined with parchment paper and allow them to cool completely and set for about 15 minutes.

If desired, sprinkle edible glitter or add chocolate drizzle on top to elevate their spooky appearance.