The Pyxians are a race of psychics from the planet Pyx located somewhere in the Gamma Quadrant.
Physiology
The Pyxians are a race of telepathic creatures that are able to use mind-boosters, projecting an artificial reality—like in holosuites—though the experience is still real to those involved in the illusion. They are quite powerful at projecting illusions, able to even project replicas of themselves across many light-years, even through a wormhole.
Pyxian are a metamorphological species, young Pyxians resemble a rhino covered with a golden fur the size of a dog. This stage of their form is called Solitary. Eventually the young will wrap a cocoon around itself, and emerge as a humanoid Pyxian.
History
In 2370, the Ulysses docked at Deep Space 9 after a mission in the Gamma Quadrant where the crewmember Darm had discovered an animal that was in fact a Pyxian prince. (DS9 novel: The Pet)
Culture
The Pyxians are a isolationist people, as their only real defense is their ability to camouflage, direct contact of any kind makes them vulnerable. Thus they refrain from making contact with other races at all costs.
Source