Heat oven to 450°F. Remove pie crust from pouch; unroll on ungreased large cookie sheet. If desired, flute edge. Generously prick crust with fork.
Bake 8 to 10 minutes or until lightly browned. Cool completely, about 15 minutes.
Meanwhile, in small bowl, mix powdered sugar, peanut butter and enough milk until smooth and desired spreading consistency.
Spread peanut butter mixture over cooled baked crust. Sprinkle evenly with chopped candy; drizzle with chocolate and caramel toppings. Cut into wedges to serve.