In an early attempt to make milk more exciting to youngsters an Upstate New York dairy [Dairylea] came out with a flavored milk.
It was a mix of whole milk and Hires Root Beer that was simply called RootBeer Milk. It was supposed to taste like a root beer float. It tasted like it came out of your car’s radiator and looked about the same. It lasted for about 5 months before it disappeared for good.