The glommer is a predator genetically engineered by Klingons to hunt, kill and eat tribbles. The first of its kind was stolen by Cyrano Jones in 2269, who claimed it under the space salvage laws. After the Glommer was introduced to the Tribble homeworld it evolved and new breed were developed such as Migratory glommers who follow the weather patterns and cold-weather glommers who fatten up for their winter hibernation.
That same year, Captain James T. Kirk rescued Cyrano Jones from the Klingons. Jones brought the glommer with him onto the USS Enterprise. After the tribbles grew to be enormous, the glommer did not seem so eager to eat them. (TAS: "More Tribbles, More Troubles")