The frozen dessert was first introduced last year leading up to St. Patrick's Day, which is around the time I reviewed it. You have to get the 20-ounce medium to get all the bells and whistles as other sizes will only include the syrup and vanilla shake base.
The medium goes for $2.89 (may vary with location).
Nutritional Info - Arby's Mint Chocolate Swirl Shake - 20 oz (517g)
Calories - 750 (from Fat - 230)
Fat - 26g (Saturated Fat - 18g)
Sodium - 450mg
Carbs - 119g (Sugar - 99g)
Protein - 16g