If making on the stovetop bring karo syrup to a boil and then add peanut butter.
Have your 5-6 cups of rice krispy cereal ready in a bowl to pour mixture on top of this immediately and stir well. I use 5 c. because I like them really ooey gooey. Stir well until combined and all cereal is coated.
Have a greased 9x12 pan ready and pour mixture in and press flat.
Melt your chocolate chips and butterscotch chips in a microwave safe bowl until melted. Put in for 30 sec., stir, 30 sec. stir until melted and then pour on top of rice krispy mixture.
Smooth over the top and leave to set, or put in fridge to harden top coat, then cut and serve. You can use cheerios too, but rice krispies are our favorite for scotcheroos!!!