Place Rice Krispy Cereal into a large bowl.
In a pot, over medium heat, melt butter.
Once butter is melted, Put the marshmallows into the pot. Stir constantly until marshmallows are fully melted and incorporated with the butter. Add in vanilla and salt.
Pour Marshmallow mixture over top of the Rice Krispy Cereal in the bowl.
Mix until about halfway incorporated. Distribute the rainbow non pareils and the chopped frosted animal crackers overtop.
Finish mixing the Rice Krispy Treat Mix until all the Rice Krispies are coated.
Place mixture into a 9″x13″ pan that is nonstick or lined with parchment paper and press down evenly over top. Making sure not to press down too much or the treats will become dense.