The glommer was 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 breeds emerged, such as migratory glommers that followed the weather patterns and cold-weather glommers that fattened 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")