In a small, non-stick pan, melt the butter over medium heat. Once the butter is melted, add the Fluff, and stir, stir, stir until the Fluff and butter are combined and the Fluff is melted.
In a large bowl, dump in the Rice Krispies, pretzels, and Oreos. Pour in the Fluff mixture and stir, stir, stir until the Fluff is mixed in evenly with the Rice Krispies. Once everything is mixed and cooled down a bit, add the chocolate chips and peanut butter chips and stir just a few times until mixed well (any more time and the chocolate and peanut butter might start to melt.)
Pour into a 9×13 pan and push it into the pan. Once the treats are cooled, cut into 24 squares.