Spray a 13 x 9 x 2-inch baking dish with non-stick cooking spray.
In a large saucepan over medium heat, melt the butter. Stir in the marshmallows and heat until the marshmallows are melted.
Stir the cake mix into the melted marshmallow mixture until combined.
In a large bowl, combine the cereal and melted marshmallow mixture. Stir in ½ of the bottle of sprinkles
Press the cereal/marshmallow mixture into the prepared pan and sprinkle with the remaining sprinkles on top.
Allow the treats to set up in the pan for 30 minutes before cutting. Use a knife with cooking spray to help them cut easily!
Notes
*With the remaining cake mix you can also made some cake batter cookies. All you would have to do is measure 6 oz of cake mix and 1/4 cup canola oil and 1 egg. Form that into balls and bake at 350 for 10-12 minutes.