Place 12 Oreo cookies into a food processor and grind into crumbs. Stir in melted butter. Press mixture into the bottom and up the sides of a 6-inch springform pan. Freeze.
Stir chocolate ice cream to soften. Measure out 2 cups. Remove crust from freezer and spread ice cream evenly into the bottom. Break up remaining 4 oreos and place on top of ice cream. Microwave peanut butter 30 seconds and drizzle over oreos evenly. Freeze.
In a large bowl, whip cream with powdered sugar and vanilla until stiff peaks form. Spread over top of peanut butter layer evenly. Freeze 6-8 hours or until completely solid.
To serve, remove from freezer and sit 10 minutes. During this time, microwave caramel with peanut butter to create the drizzle over top.
After 10 minutes, remove sides of springform pan. Use a sharp knife dipped into hot water to slice easily. Drizzle peanut butter caramel sauce over top and serve.