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

Add the marshmallows, stirring continuously over medium-low heat.

As the marshmallows begin to melt, add enough gel food color to achieve your desired color. Stir well.

Remove from heat and stir in the Rice Krispies until everything is well incorporated.

Let the mixture cool slightly.

Spray your hands with non-stick cooking spray, then shape the mixture into balls.

Push a pretzel rod into the middle of each ball, adjust its shape, and set it on a greased plate.

Cut out leaves from the fondant and mark them with veins.

Add the leaves to the Halloween Rice Krispie treats, and you're done!