Sehlat

This is a list of fictional extraterrestrial animal species from the science fiction universe of Star Trek. Like other aspects of stories in the franchise, they were recurring plot elements from one episode to another and sometimes from one series to another. Some have gained significance beyond the dedicated fans of the series; the furry, fast-breeding tribble has gained a place in popular culture and language.

This list describes the more notable fictional animals featured in Star Trek films or multiple episodes.

The Cardassian vole is a fictional rodent species in the series Star Trek: Deep Space Nine. It was a pest aboard the space station, infesting Quark's Bar as well as Ops where it chewed through wiring. It is quite unlike the voles of Earth, most notably in that it has six legs. It is also much bigger than a terrestrial vole.

Although he has denied it, Quark hosts vole fights. Morn has been known to assist him in setting up the events by painting numbers on the voles' backs.

The Ceti eel appears in the 1982 film Star Trek II: The Wrath of Khan. It is the only indigenous lifeform of Ceti Alpha V known to have survived after Ceti Alpha VI exploded and sent Ceti Alpha V into a different orbit. Ceti eels incubate their larvae between protective plates that line their backs. The slime-covered larva will seek out a larger animal, enter its skull through the ear and wrap itself around the cerebral cortex. This causes the subject intense pain and makes them susceptible to suggestion. As the larva grows, the host suffers from insanity and eventual death. Ceti eels bear a remarkable resemblance to antlion larvae.

...
Wikipedia