Add peanut butter to a glass bowl and heat in microwave for 30-60 seconds until melted.

In another bowl, mix flour and sugar together.

Remove peanut butter from microwave and add flour and sugar combination 1 tablespoon at a time and stir. Gradually add enough flour until peanut butter turns doughy where you can manipulate it.

Add chocolate chips to a glass bowl and heat in microwave for 30-60 seconds until melted.

Stir in marshmallow fluff and 2 tablespoons of cornstarch. Heat for another 30 seconds if needed.

Dust a handful of corn starch on a plate or counter top and knead the chocolate slime a few minutes in the cornstarch. Add more cornstarch if too sticky.

Add a bottom layer of chocolate slime flatten with a spoon, then add a middle layer of peanut butter slime flatten with a spoon and a top layer of chocolate slime to cupcake liners.

Chill in refrigerator for a hour, remove paper liners and play!