Rock-a-Stack is a toy by Fisher-Price for young children. It consists of five colorful rings stacked onto a ring base.
It is first seen in Tin Toy as one of Billy's toys.
Andy also has a rock-a-stack, seen under Molly's crib in Toy Story. Seeming to have outgrown it, the now-forgotten rock-a-stack was seen on Andy's shelf, as seen in Toy Story 2, now missing two rings one was pulled out of the toy box during the Green Army Men's search for Woody's hat. Seeing this, Mrs. Davis took this out to be sold at a yard sale.
A different rock-a-stack is seen in the the Caterpillar Room at Sunnyside Daycare in Toy Story 3.
- In addition, the colors of the rock-a-stack rings changed from the ones originally presented in Toy Story. The new colors reflect the newer rock-a-stack model in real life.