The Perigrum is a predatory animal native to the Sidhverse. Often found dwelling underground, perigrums have gained a reputation for ferocity, preying on whatever creatures happen to stray into their territory.
Perigrums are omnivorous, solitary predators of opportunity, stalking their targets from out of their sight as they wait for the chance to attack. Once such a chance arises, they leap at their unsuspecting prey with an ear-splitting shriek, sinking their claws and teeth into their flesh as they tear the helpless creature apart. However, perigrums are just as curious as they are vicious; sometimes they will approach an unfamiliar face to investigate. The action that usually follows is an attempt to subdue the newcomer and devour it.
The average meal of a perigrum is the birdlike greasel, which often shares its typical subterranean habitats. Larger perigrums will chase after viperwolves and even target baby pantheraptors and titanosuchi that happen to wander into their domain. However, if the opportunity arises, they are happy to go for humans or Sidhae, and indeed display an uncanny preference for consuming sapient beings. If all else fails, however, a hungry perigrum can occasionally be found picking through garbage or fishing in a stream for its lunch.
The appearance of perigrums varies from planet to planet. Those that dwell on terrestrial worlds have short arms, mahogany skin and a grey segmented carapace covering the top of its head and along its back, along with a short, stumpy tail. They almost resemble a small bipedal dinosaur, slouching at just over a head taller than the average man. Their larger death world-dwelling cousins, however, grow to the size of elephants, have much better developed arms, long whiplash-like tails, jet-black bulletproof carapaces extending all over their entire body, and razor-sharp claws capable of shredding through power armour with laughable ease. Their most notable trait, however, is their extremely corrosive blood, able to erode even hardened stone in but a few seconds. It is their acid blood more than any other aspect of their biology that serves as the chief reason why no animal dares to prey on the perigrum.
The exact origin of the perigrum is hotly debated among the galactic xenobiology community. One theory suggests that they are living weapons created via genetic engineering, but who (or what) created them is still unclear. Many assert that it was the Skargh, citing records from the Skargh Wars of the creatures being used by the reptilian techno-barbarians in a similar role to war-hounds. Some date their creation to as early as World War IV, where their similar appearance to vicious creatures in Old Terran horror movies allowed them to be used as terror weapons. A more eccentric group of theorists ascribe their creation to an as-of-yet undiscovered precursor civilisation.
If the perigrum is a naturally-occurring xeno, its native habitat is likely to have been a molten hellscape, with its dangerously corrosive blood possibly being a result of a highly-sulphuric atmosphere created by constant volcanic eruptions. Whatever creature(s) it hunted must have been heavily armoured to necessitate the evolution of its molecule-sharp claws and boltcutter-like teeth. Additionally, there is the theory that its acidic blood is a defence and deterrence mechanism, which suggests that the perigrum was likely not even the apex predator of its native environs. Although, what kind of ineffable monstrosity such a deadly world could possibly spawn to fulfil that role is up for debate – but what cannot be doubted is that such a grand beast would fetch the eye of every accomplished Sidh trophy hunter looking for a real challenge.
Whatever its origins, the monstrous perigrums have been appropriated by the Imperium's Domestic Security, who set them loose in catacombs beneath human ghettos to stop undesirables from wandering into their towns from below.
Perigrums quite obviously borrow influence from the Aliens/Xenomorphs from the eponymous franchise, though the creature itself takes its name from the Perigrum Forma, a type of demon in science-fantasy computer game E.Y.E: Divine Cybermancy.