The Trofars were a pre-warp culture that existed in the Gamma Quadrant.
The Trofars are a diminutive race, only about one meter tall, and very stocky, covered in dark hair. They more or less looked like trolls, with two bright eyes, slits for nostrils, and large, hairy feet. By the 24th century at least a few of the Trofars had underwent a forced adaptation by the Cardassians, who had altered the Trofars, making them utterly dependent on electronic implants. These implants controlled their vital functions, shielded them from sensor detection and also allowed them to pass through force fields undetected. (DS9 novel: Field Trip)
Sometime after the discovery of the Bajoran wormhole, the Cardassian Union had surveyed the Trofar homeworld, where they discovered the sentient race. The Cardassians found the Trofars to be highly adept at camouflage and hiding, though thanks to their technology the Cardassians managed to capture a group of Trofars and took them back for study. The Cardassian scientists altered the Trofars, implanting them with anti-sensor dampeners, with the intents in using the Trofars in espionage. However the Trofars protested this, and led by Lek, they managed to escape captivity, but the Cardassians managed to damage their ship forcing the aliens to crash on a nearby jungle planet. Thanks to their implants the Trofars evaded recapture, but due to their enhancements they were totally dependent of the implants and needed new ones for the new generation. When Keiko O'Brien's class shuttle was shot down by the Cardassians, the Trofars ransacked their shuttle for parts for their children.
The two groups formed alliance to survive against the Cardassians and managed to overpower the Cardassian away team and steal a shuttle back to Deep Space 9. Afterwards the altered Trofars were given asylum by Sisko who also offered Lek a chance for his kind to have their enhancements reversed so that they may rejoin the mainstream Trofars. (DS9 novel: Field Trip)