Add the chocolate syrup into a baggie and cut a small hole out of the corner. Pipe the syrup on the outside of the glass and on the rim of the glass. Let it drip down some.
Remove the filling from the chocolate sandwich cookies. Crush the cookies to make the crumbs. Add to a shallow dish that is bigger than your mug.
Dip the rim of the mug into the cookie crumbs.
Scoop 1 - 2 scoops of ice cream into the glass. My glass was small, so I did one.
Pour the A&W Root Beer over top of the ice cream. Let the foam go down and pour more in until the mug is full.