To prepare the fudge sauce, in a small saucepan, melt the chocolate and butter over low heat and stir until smooth.
Add the sugar, cocoa, corn syrup and water. Cook until the sugar dissolves.
Bring the mixture to a boil and cook on low heat, without stirring, until the mixture thickens, or about 15 minutes.
Remove from the heat and stir in the vanilla. Set this aside to cool.
Make the Oreo crust:
In a small bowl, mix together the cookie crumbs and butter.
Press the Oreo mixture into the bottom and up the sides of a 9" pie pan. Set aside.
Make the ice cream filling:
In a medium-size bowl, mix together the marshmallows, chocolate chips and softened ice cream until completely combined.
Once the fudge sauce is lukewarm, pour this over the cookie crust. Then spoon the ice cream mixture over the fudge and smooth the top with a spoon.
Drizzle the top of the pie with caramel.
Cover the pie and freeze it for at least 2 hours.
Serve with whipped cream and cherries if desired.
The calories shown are based on the pie being cut into 8 pieces, with 1 serving being 1 slice of pie. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**