Anybody ever heard of a Boston Shake?
In the Midwest (Illinois, at least) you could order them from Dairy Queen or most places. It is a large cup, filled 3/4 full with a chocolate shake, then they put vanilla ice cream on the top, cover it with hot fudge and whipped cream and a cherry…so basically, you had a hot fudge sundae floating on top of a chocolate shake.
Even as a fit, healthy young kid, you could only have about one of those a month, but boy were those good!