Back in the 1960s there were some shakeable foods that my sisters and I used to love to make. Both were based on the same idea. They came with a cup with a lid, and a tetrahedronical envelope of powder. You tore the end off an envelope, poured the powder into the cup, added milk, and shook the cup.
One of these products was Royal's Shake-A-Pudd'n. As you might guess, the agitation of shaking the powder and milk caused the mixture to set into a smooth pudding. Their commercials started with a jingle singing, "Pudd'n, Pudd'n, Shake-A-Pudd'n".
Then there was Great Shakes, a similar idea, but instead of pudding, you ended up with a frothy milk shake. Below is a Great Shakes commercial, courtesy of You Tube. These were great fun as a kid, and as I recall they didn't taste too bad either.