The Stonebacks were reptiles from the asteroid called Algol. The creatures lived in subterranean glass or crystal houses. The Stone-Backs captured prey by curling up into their shells and camouflaging themselves as rocks. They had a primitive language, however one of the Stone-Backs named Gluck could speak English. Their religion was based on the worship of a giant turtle god which they confused for a stranded space marine Steve while in his space suit.