Grease a 9- by 11-inch baking pan with butter.

Melt the butter in a large pot over medium heat. Add the marshmallows, and stir until melted and smooth. Add the cereal and mix well. Working quickly, add the chocolate chips. (Depending on the temperature of the crispy mix, your chips may melt and you'll have chocolate crispy squares. If you add them as the mixture gets stiff and cool, they'll stay intact as chips. It's completely up to you.)

Spread the mixture out evenly into the greased pan with an oiled spatula or waxed paper, pressing down gently to fit it into the pan. Dust the top with rainbow sprinkles and refrigerate. When cool, cut into 1-inch squares.

Pour 2 to 3 inches of liquid nitrogen very slowly into a stainless steel bowl. Make sure to wear your goggles and gloves!

Drop 8 to 10 crispy squares into the liquid nitrogen for 30 to 40 seconds. Scoop them out with a slotted spoon and place on a serving plate. Wait 10 seconds then eat the squares. You will have some 'dragon's breath' coming out of your mouth and nose. Thrills and chills will ensue!