Pulse Oreo cookies in a food processor until you have fine crumbles that resemble coarse coffee grounds.
Set aside ½ cup of the crumbles for the topping.
Pulse together the remaining crumbles with the melted butter in the food processor.
Press the cookie mixture out in an even layer into the bottom of a large casserole dish to form the crust.
Place in the refrigerator to chill for 30 minutes.
In the bowl of a stand mixer, beat together the softened cream cheese, powdered sugar and half the whipped topping. Reserve the other half of the whipped topping for the top layer of the pie.
Spread the cream cheese mixture evenly over the chilled Orea cookie crust.
Return to the refrigerator for 30-60 minutes.
Whisk together the chocolate pudding mix, vanilla pudding mix and the 3 cups milk until smooth.
Spread the pudding mixture evenly over the cream cheese layer.
Return to the refrigerator for another 30-60 minutes or until pudding sets up.
Spread the remaining whipped topping over the pudding layer.
Cover and refrigerate until ready to serve.
To serve, sprinkle with reserved Oreo cookie crumbles and drizzle with chocolate syrup, cut into squares.