Blackstalker

The Blackstalker was a genetically-engineered offshoot of the Garral created by Imperial scientists expanding on the work of Luthos Garral. The Galactic Empire intended to use them to assist human scouts and guard patrols, but they proved to be very aggressive and nearly impossible to train. Their creators attempted to destroy them before they were put into service, but many managed to escape on outbound starships.

Biology and appearance
Despite being closely related to Garrals, Blackstalkers only slightly resembled their more common cousins. While both were quadrupedal, with clawed feet, powerful jaws, and tails, Blackstalkers lacked fur. Instead they were covered in tiny black scales, which were strong enough to deflect light blaster fire. They were two meters long, and could live for as long as fifty years.

Unlike Garrals, Blackstalkers were not adversely affected by the ultrasonic noises of repulsorlifts. As a result of the tampering with their genetics they also gained a very basic ability to use the Force. Normally they manifested this ability to manifest a primitive form of Force Stealth, but when cornered they were also known to use the Force to bolster their combat ability.

While Garrals possessed a pack mentality, Blackstalkers rarely tolerated any other living beings, even members of their own kind. Normally they would either attack or avoid any creature except for their mate and offspring. They mated for life, producing one to two cubs at intervals of several years, and defended their young fiercely, attacking any potentially threatening creature that approached.

Despite this general hostility, Blackstalkers were known to bond to sentient creatures from time to time. Most such bonds developed when the Blackstalkers were young and impressionable, but sometimes those who treated injured Blackstalkers were bonded to, though equally often they were attacked anyway. Bonded sentients were treated as family members, and even allowed to approach the creatures' young. Very rarely, toleration would be grudgingly extended to the bonded creature's companions.

History
After the success of the Garral as a guard beast on frontier worlds, Imperial scientists continued to experiment with the creature's genetic code at an unknown facility. The result, an unknown time before the Battle of Endor, was the first Blackstalker. A large number of the creatures were created, but after many attempts the scientists in charge of the project found it impossible to domesticate or control them by any means. Because of this, they ordered the destruction of all Blackstalkers.

Likely using their Force abilities, many Blackstalkers managed to escape the facility and stow away on starships departing from the area, spreading across the galaxy. The Galactic Empire posted significant bounties on the heads of the creatures, drawing the attention of many bounty hunters, but only a few managed to actually catch even one of the deadly beasts. It has been speculated that this is because an unknown organization transported many Blackstalkers to a mostly uninhabited planet where they were unlikely to be found.

Though extremely rare due to their aggressive behavior and limited starting numbers, Blackstalkers continued to be sighted throughout the New Jedi Order era.

Notes and references
Blackstalker