In a large (microwave safe) bowl, place butter and marshmallows. Heat in the microwave for 30 seconds. Mix well. Heat for another 25 seconds and mix until completely melted.
Add the Rice Krispies cereal to the marshmallow mixture. Mix well.
Lightly grease an 8x8 baking pan. Transfer the krispies mixture into pan, spread it evenly and press it down.
Refrigerate while preparing the chocolate, to set in.
Place the white chocolate in the microwavable bowl. Microwave it for a minute on half the power. Stir and heat it for 30 more second (*on half the power*), if it's still not completely melted.
Use the same process for the milk chocolate but start with 30 seconds. Transfer the milk chocolate into a piping bag with #102 decorative tip.
Cut the rice krispies into eight equal rectangles. Dip the krispies in white chocolate and let it set for a few minutes.
Drizzle the milk chocolate to form mummy wrap. Don't worry about being really neat because...well, mummies are not neat!