Adamantium

Imagine a leech. A leech over a foot long and half a foot in diameter. With a row of rippling thin millipede legs down each side, giving it disturbingly high speeds on the ground and climbing skill like no other. Its glistening black body secretes a mild neurotoxin, made to numb or paralyze those that come in contact with it, especially its preferred prey, headhuggers.

Its mouth is an oval filled with shifting daggerlike teeth, serrated to a microscopic degree, made for slowly sawing through hard materials to get to the soft interiors of a headhugger...or other animal's torso, if it has become deperate for food. Blind and deaf, but half telepathic, it's sensory abilities focus mostly on seeking out the same mental wavelengths that headhuggers use, but that also can include some other mammal mental levels, including humanoid beings.

A single one of these creatures is called an adamantia, and usually travel alone, unless starving. Then they start to gather and hunt in packs after larger prey, sating temporary hunger before seeking out their preferred prey of Headhugger. When in groups, they are called adamantium.

Insane people, typically warped by chaos withdrawal will try and capture adamantium and place them on their bodies to make clothing out of them, claiming it is armor, as it numbs sensation of any contact with them. Of course, soon after, the person is paralyzed from constant toxin exposure from the willingly attached creatures, then penetrated by the starving group as they burrow into his body and devour his innards. This usually ends the insanity rather quickly.