In Larry Niven's fictional Known Space universe, the Thrintun (singular Thrint) were a long-extinct species which ruled the galaxy through telepathic mind control. The Thrintun were destroyed about 2 billion years before the human era, in a story partially told in the novella World of Ptavvs. Their original name was unknown before the setting of the novella, but traces of their culture had been discovered and they were simply referred to as the slavers.
The Thrintun settled huge amounts of the galaxy, seeding many planets with basic life forms (created for them by one of their controlled species, the Tnuctipun) to use as food sources. Once the photocycle was established, larger animals known (to humans) as the Bandersnatchi were introduced in an example of interstellar cattle-farming. Humans evolved from one such planet, which was abandoned when the Thrintun culture was destroyed, after photosynthesis had started, but before the Bandersnatchi had been moved in. Humans are, in the Known Space universe, evolved cattle-feed.
A number of their technologies, in particular their engineered life forms, continue to exist in the human era. Among these are trees that mature containing solid rocket fuel in their trunks, originally used as cheap rocket boosters when planted in orchards, but now evolved to be able to seed themselves across star systems. Their interstellar drive system is the basis for all FTL travel in Known Space. Discovery of a slaver stasis vault, often containing new and tremendously valuable technologies, was a pastime of many gentleman-adventurers.
