Bullsquids are alien animals that appear in the video game Half-Life. Appearing in Black Mesa following the Resonance Cascade, they were brought from Xen in the ensuing portal storms. They appear to be amphibious as they are commonly found in watery areas; they can even survive in inhospitable areas such as sewers and even in pools of radioactive chemicals.
The body of a Bullsquid is vaguely similar in appearance to that of a small Theropod, with two short, muscular legs and a thick tail that tapers to a point. The thorax abruptly joins the creature's head with no neck or other visible separation. A typical specimen stands roughly one meter tall and about two meters in length. Two slit-pupiled, black and glossy eyes are mounted on either side of its head. The tail had a hooked claw at its tip, which explains the large amount of damage caused by the Bullsquid's spin attack.
The Bullsquid's most striking feature however, is a collection of bright red, Cthulhu-esque, tentacles surrounding its mouth and allowing it to grasp prey. The Bullsquid can also charge an opponent with surprising speed and force; these two attributes are likely the cause of its portmanteau name.
The Bullsquid's overall coloration is roughly comparable to that of a spotted cat: its skin is sandy brown and its upper surfaces has dark spots. The creature's skin appears to be slimy, similar to that of a terrestrial amphibian such as the frog.
The Bullsquid has an array of offensive capabilities. They display a very territorial disposition, as they have often been seen attacking other creatures and even members of their own species. They viciously attack Headcrabs, not stopping until all Headcrabs in their sight are eliminated, while they do not harm Houndeyes. They however do not attack, even when attacked themselves, when encountered during the Resonance Cascade in Half-Life and in the same map in Opposing Force. They are drinking from a Healing Pool both times, however, so it is likely that they are simply not aggressive while feeding or drinking or that they cannot see the player somehow.
At close range, a hostile Bullsquid will either maul its victim with its teeth, or suddenly spin around, delivering a powerful strike with its tail, often causing gibbing. At long range, the Bullsquid is able to spit a toxic, bile-colored substance from its mouth, like the Antlion Worker. While not particularly accurate or fast, it causes moderate damage, even at very long range.