Lightly grease a 9x13 inch baking dish with cooking spray (or line with parchment paper) and set aside.
Melt the butter in a large pot over low heat. When the butter has completely melted, add in the mini marshmallows and stir to coat. Continue to heat the marshmallows, stirring often, until they are completely melted.
Remove from heat and stir in the vanilla extract. Add the cereal to the melted marshmallows and stir to combine.
Gently press the cereal mixture into prepared pan and allow to set for 15 minutes.
As the treats are setting, add the white chocolate chips and coconut oil or shortening to a small saucepan. Heat over low heat, stirring frequently, until melted and smooth.
Cut the treats into 16 rectangles. Gently press a craft stick into the middle of each rectangle. Dip each treat halfway into the melted chocolate and sprinkle with pop rocks.
Place the dipped treats onto a baking sheet covered with parchment or wax paper or on a wire rack to set. You can allow them to set at room temperature or stick them in the refrigerator to set a little faster.