This was made by Nestle and was like a milkshake.
My parents bought it very occasionally, but it was a real treat when they did buy it. It was quite sweet, and came in a few different flavours - Strawberry, Vanilla and Chocolate.
Nesquick was the powder that you put into milk to make it flavoured like a milkshake. It pretty much tasted like flavoured milk but was great.
I think you can still buy it some places, and they even made it into a cereal as well!