Prepare the baking pan by lining it with parchment paper or lightly greasing it with butter.

In a large pot over low heat, melt 4 tablespoons of unsalted butter, then add the mini marshmallows and stir until smooth.

Once melted, fold in the Rice Krispie cereal until evenly coated.

Press the mixture into the prepared pan with buttered hands or parchment paper to ensure even thickness.

Cool the treats at room temperature for 30-60 minutes, then cut into squares or shapes.

Melt green and black candy melts, drizzle over treats, and add decorations as desired.

Let the decorations set for 15-30 minutes, then serve and enjoy!

Store leftovers in an airtight container at room temperature for up to 3 days.