These flimsy humanoid creatures native to Mars are presumed to be the natural food source of the sapient, cephalopod-like Martians, which feed upon them by means of injecting the prey's blood directly into their own veins. They are thin creatures, about six feet in height, and have siliceous skeletons, similar to those of siliceous sponges. Their heads are round, and have large eyes located in flinty sockets.