Amphi-Hydrus

The Amphi-Hydrus are a race of amphibious beings indigenous to the water planet of Dac, more commonly known by its nickname, Mon Calamari. Likely due in whole to their physically frail bodies, they became masters of mind control through use of their sensitivity to the dark side the Force. Just prior to the subjugation of the planet Dac by the Galactic Empire, they had succeeded in gaining a foothold over the entire planet through the use of their telepathic capabilities, which allowed them to take over the minds of a few rancors that had been imported to the world. With these, they wreaked havoc everywhere they moved from the safety of the backs of these monstrous, occasionally semi-sapient beasts. This all came to an end for them however when the Galactic Empire attacked the planet, and they soon reverted to a life of swamp dwellers, where they bitterly awaited the chance to recapture their previously ill-obtained domination.

Trivia

 * The Amphi-Hydrus were created by Daren Horley, a Star Wars fan, through the Design An Alien contest held within the Star Wars Galaxy Magazine. While not picked as the overall winner, it was given an honorable mention, and is considered as an existent organisms by a Lucasfilm official.
 * Their race bears a very curious resemblance to the Dnyarri of the Star Control universe, not only through their astute mind-control abilities but also through their physical appearance as well (similar to the Hypnotoads of Futurama fame. This may indicate where he obtained his inspiration from, or may just be coincidental.