Start by lining your 8x8 baking pan with a piece of parchment paper. Spray the bottom of the pan, bowl, rubber spatula, and knife with nonstick cooking spray. Set the pan to the side.

Melt the unsalted butter in a medium saucepan over medium-low heat.

Add marshmallows and continue to stir using a rubber spatula until marshmallows have melted, and remove from heat.

Add a few drops of green food coloring to the mixture till you get the desired shade of green.

In a large bowl, pour your rice cereal and then fold in your green marshmallow mixture. Stir till it is completely combined.

Add the green color rice crispies to the pan and gently press down. Let the bars cool down for 1 hour at room temperature and cut them into nine pieces.

To make royal icing, combine powdered sugar, meringue powder, water, and a few drops of black food coloring.

Decorate each treat with black royal icing, candy eyeballs, and M&M's as ears.

Enjoy!