In a large bowl, combine the cookie crumbs, butter and sugar. Press into a 9-in. pie plate. Bake at 375° for 8-10 minutes or until set; cool completely on a wire rack.
In a large bowl, beat cream cheese and chocolate syrup until blended. Beat in melted chips. Set aside 1/4 cup of whipped topping. Fold marshmallows and remaining whipped topping into chocolate mixture.
Spoon filling into crust. Refrigerate for at least 8 hours or overnight. Top with reserved whipped topping. Garnish with chocolate curls if desired. Yield: 8 servings.