Line an 8-inch square baking pan with parchment paper and grease with a little oil.
In a saucepan over low heat, add you butter, marshmallows, dark chocolate, cocoa powder, and salt.
Let that stand in the pan for 1-2 minutes and then start to stir frequently until the mixture is smooth and combined, basically a chocolate marshmallow fluff.
Lightly grease a large bowl. Add the chocolate rice cereal to the bowl and pour the marshmallow fluff over the cereal and fold until the cereal is thoroughly coated. Sometimes I like to use my hands here, but they will get sticky!
Scrape the mixture into the prepared baking pan and using your hand or the back of a measuring cup, press evenly into the pan.
Let that cool in the freezer for 15 minutes, or in the fridge for 1-2 hours.
Right before you pull your rice crispy treats from the fridge/freezer, start to melt you white chocolate.
Over low heat add your white chocolate. Let it stand for 1-2 minutes until you see the bottom get melty, then stir together with a spatula. Melt more white chocolate if needed, depending on how you will decorate.
Cut the rice crispy treats into 9 squares and coat with the white chocolate. Freeze for 5 minutes, then drizzle on the mummy wrap. Place a dot of white chocolate behind the candy eyes and place on the bars.