Bake the cupcakes with the oil, butter and eggs as directed on the package. Let them cool completely. Once cool, blend the green food coloring and fluffy white icing together. Ice the cupcakes with a thick layer of icing. Add sprinkles to decorate. You can use the tip of a fork to 'pull' the icing up to look like grass blades. Use a serrated knife to cut a large marshmallow in thirds. Stick the cut side of one piece on the cupcake as the 'butt'. Add two small marshmallows as 'feet'. Use the tubes of purple and pink icing to create the tail. Use the writing icing to create the feet.
Recipe by A Day in Motherhood at https://www.adayinmotherhood.com/bunny-butt-cupcakes/