Combine marshmallows and butter in a
large glass bowl and microwave until
melted, about 1 minute. Stir until
smooth. Tint mixture to a bright green
with green and yellow food coloring.
Add cereal and stir until well coated.
Let cool about 5 minutes. With greased
hands, shape about 1/3 cup of the mixture
into a small cone, pressing firmly.
Decorate cone with red sprinkles. Repeat
with remaining cereal and sprinkles. Top
each cone with a yellow candy and place
on top of a peanut butter cup.