This is the best way to savor and enjoy a root beer float.
Get a tall, transparent glass, preferably retro. Use real, brand name ice cream, and pick New York Vanilla or Homemade Vanilla. Put a cherry on the bottom. Put three scoops into the glass (or until the stacked scoops take up 3/4 of the glass). Pour name brand root beer(doesn’t matter if it’s caffienated or caffiene free) slowly over the ice cream until the foam mass on top reaches the critical point when you don’t know whether it’s going to fall over or not. Eat the foam with your mouth, not a spoon. Then use a spoon to eat the ice cream slowly, dipping each spoonful back into the root beer and swirling it around so it absorbs the carbonated rootbeer taste before you put it into your mouth. When the ice cream is all gone, drink the melted ice cream/root beer. Then, eat the cherry which had been marinating during the whole process.