Prepare the Milkshake: Combine the chocolate ice cream, milk, and creamy peanut butter in a blender. Blend until smooth.
Decorate the Glasses: Spread chocolate frosting on the outside of the glasses, covering 2-3 inches from the top. Press chopped Oreos, mini peanut butter cups, and chopped peanuts into the frosting.
Add Chocolate Syrup: Drizzle chocolate syrup down the inside of the glasses.
Assemble the Milkshake: Pour the milkshake into the prepared glasses. Top with whipped cream.
Add Toppings: Skewer cupcakes through straws (optional) and decorate with additional toppings like more peanuts, cookies, and peanut butter cups.
Serve and Enjoy: Serve immediately and enjoy your epic chocolate peanut butter milkshakes!