Shibboleth is a quadrupedal beast from the Gears of War universe. Appearing in Gears of War: Judgment, it served as the personal mount of the Locust general, Karn. Whereas other Locust beasts had to be beaten and forced into service, Shibboleth served Karn of its own volition having developed a kinship with him.
Like many creatures of the Hollow, Shibboleth's biology is inconclusive as it possesses various traits common to reptiles, insects and crustaceans. It has four multi-jointed spider- or crab-like legs and white leathery skin. Its body has been outfitted with metallic armour and carries various weapons mounted to it, such as Troika machine-guns, incendiary grenades, Imulsion launchers, Nemacyst and also Digger Launchers. One of its legs is also entirely mechanical; when Karn originally discovered Shibboleth, it had a mangled leg which would be amputated and replaced with a cybernetic prosthesis.
Sometime before the Locust War, Shibboleth had damaged its leg and was found by a wandering Karn. Karn saw himself within the beast, alone and forgotten, and decided to construct it a new leg in order for it to walk again. Shibboleth bonded to Karn and became his ever-faithful mount.
When the war began, Karn had masterminded the Locust's original invasion plans and had personally overseen the fall of Gorasnaya, riding Shibboleth into battle and decimating the UIR forces. Later, Karn would personally lead the Locust against the COG at Halvo Bay, bringing the city to ruin. Kilo Squad, a group of Gears led by Damon Baird, attempted to stop Karn's rampage by launching the COG's latest weapon of mass destruction, the Lightmass Missile. The missile succeeded in destroying most of the Locust forces, but Karn and his mount survived the attack.
While Kilo Squad were being put on trial for using the Lightmass Missile without authorization, Karn led an attack on the courthouse in the Plaza for the Tyran Dead. Kilo Squad made their last stand there in the Plaza, battling valiantly against Karn and Shibboleth. They defeated the creature by attacking its prosthetic leg, leaving it prone and then shooting at the monster's mouth. Karn would live only a few seconds longer than his pet as Colonel Ezra Loomis then executed the Locust general with a bullet to his head.