Add sandwich cookies to a food processor and process for 10 seconds or until crumbly.

Mix with melted butter and press into the bottom of a 9x13 baking dish. Set aside.

Add marshmallows and milk to a large, microwave safe bowl and microwave for 60 seconds on high power.

Stir well and return to the microwave for an additional 60 seconds on high powder and stir until smooth.

Let stand to cool (about 30 minutes), stirring occasionally until cool.

Add whipped topping to the marshmallow mix and stir well. Fold in ½ cup sprinkles.

Spread on top of crust. Top with M&M candies and sprinkles. Cover and refrigerate for 1 hour before serving.

Cut into slices before serving.