The silicates are silicon-based organisms accidentally created in a laboratory explosion by Dr. Lawrence Phillips, in his quest to cure cancer. The silicates, whose name was coined by Doctors David West and Brian Stanley, were short, squatt green creatures of no discernable shape that crawled along the ground like slugs. They reproduced by fission and used their single tentacle to inject an enzyme into their victims, which liquefied their skeletons and allowed the silicates to suck the bones out.
Just beneath their lumpy green skin they had a hard shell that was nearly impenetrable, making them almost impossible to kill. The silicates overran the island where the Phillips Laboratory was located, Petrie's Island, but were finally destroyed by West and Stanley by feeding them cattle contaminated with the isotope Strontium-90. Although the entire Silicate population of Petrie's Island was wiped out in this manner, unknown to West and Stanley, colleagues of Phillips' in Tokyo, Japan performed experiments similar to Phillips' and created more Silicates. It is unknown this problem was overcome, if at all.