The toy itself consists of a metal device with two basic parts. The main section is a heating chamber, a metal grill over a heating element that is covered by a plastic dome with a sliding door. (The unit plugs into a wall outlet.) The child places a small, waxy, variously-colored cube in the chamber and it expands to become one of several different types of weird creatures. A pair of plastic tongs can be used to remove the toy from the chamber, and after cooling, it can be played with as a regular small plastic figure.
The child can also put the figure back into the heating chamber until it becomes soft, then it can be placed into a vise (the second section of the device) where it can be squeezed back into its original cube shape, complete with the Mattel logo on one side.
The toy also comes with a thin blow-mold base, shaped like rocky terrain, that the metal device sits in, as well as a larger fold-out map of a mythical world populated by the cube-monsters. (This toy is subtitled The Lost World.)
The 15"x10" box containing the toy contains colorful, striking artwork, and is fondly remembered by kids of that era.