You know St. Patrick's Day isn't too far off when the Shamrock Shake returns to McDonald's. The green drink returned as of yesterday (February 21st.) A McDonald's press release says the drink features, "creamy vanilla soft serve blended with Shamrock Shake Syrup topped with delicious whipped topping." They fast food chain even has a brand new app that can help you track the shake down called the Shamrock Shake Finder. The drink has developed a "cult-like following" since it debuted on the menu in 1970.