In a microwave-safe bowl, combine the marshmallows and butter. Microwave on high for 1 minute, then stir and continue microwaving in 30-second intervals until fully melted and smooth.

Add the food coloring to the melted marshmallow mixture and stir until evenly colored.

Fold in the Rice Bubbles until they are well coated with the marshmallow mixture.

Lightly grease the brain-shaped mold with butter or cooking spray.

Spoon the Rice Bubbles mixture into the mold, pressing down firmly to ensure they hold their shape.

Allow the mixture to cool and set for about 10 minutes.

Carefully remove the shaped brains from the mold and place them on a serving platter.

Serve immediately or store in an airtight container for up to 2 days.