The closer you get to it, the more you degrade. Your vision splits and blurs and corrodes. A fever breaks out in you. You go hot and cold. Your hands grow weak and sweaty. Your eyes grow red. You can't stop crying. You feel like a bag of broken glass. You cough up blood. Black spots growing cancerously through your sight. Your hearing pops and crackles, becomes distant and muffled, until finally you can hear nothing at all. Your legs give out underneath you. Everything feels slick under your touch, like your fingertips themselves are sloughing away.
When you are finally in its presence, you go completely blind and deaf. You have to grope your way across the floor. The heat of it burns on your skin like a tanning lamp, so you can always tell where it is. You think you can see an ultraviolet outline of it, burned into your retinas, even with your eyelids shut.
It stumbles across the floor in a way that feels sickeningly human. Like a newborn baby. In fact, don't you hear sounds coming from it, through the silence? Gasps and small sentence fragments, like the voice of a child? Perhaps it's just another hallucination.
No-one knows where they come from, but of course there are theories. Some say they were children used for teleportation experiments. Others say they're time-travellers. They were sent back to warn us before it's too late. But it has always been too late. Their machines did not do enough to shield them from the howling void outside of space and time. As they made the voyage, they were shredded apart on a molecular level. They became Outside Contaminants.
They are painfully, eternally lonely. They stumble and crawl towards any human they can find, mewling. Maybe they're still trying to warn us. They seem pathetically desparate for human contact of any kind. When a Contaminant manages to corner a human target, it will curl up with them and shiver, rubbing itself against them like a house cat. The Contaminant will continue to rub itself against them, long after they have died. You may think you hear garbled pieces of gibberish as it attempts to talk to them.
It is slow, and stumbling. But the closer it gets to you, the slower you become. Eventually it can easily catch up to you. If it touches you, it is already too late. Your organs have begun to shut down.
If you manage to escape, you will slowly recover. Your eyesight and hearing come back and get better and better the further you are away from it. You will eventually regain full mobility, but you will always feel more tired. Your bones will ache on cold nights. Your eyesight feels blurry and streaky. The parts of your body it grew closest too will always feel hot and sunburned. You don't know it yet, but you have lost 1 year off your lifespan for every minute you spent in its presence.
ENTITY 03: CONTAMINANT
Number Appearing: 1 - 2.
AC: 12. HD: 2.
Speed: 1/2 unencumbered human.
Speed: 1/2 unencumbered human.
As you get closer to the Contaminant, your corrosion level increases.
- When you are in the same area as the Contaminant (like the same building), your vision feels blurry. You get a fever. Your hearing grows dim.
- When you are only a few rooms away from the Contaminant, you begin to cough up blood. Black spots grow across your vision. You shake all over. You have disadvantage on all checks. Your movement speed slows to 1/2 your normal speed.
- When you are in the same room as the Contaminant, you go completely blind and deaf. Your legs give out and you must crawl. You feel weak. All dice you use go down 1 size (All d20's become d12's, d12's become d10's, etc). Your movement slows to 1/4th of your normal speed.
- If the Contaminant touches you, your organs begin to shut down. You permanently lose 1/10th of your maximum HP every round. (If your maximum HP is 100, you would lose 10, then 9, then 8, etc). Your movement slows to 1 square per round. All dice go down 1 more size.
Killing the Contaminant does not stop the contamination. If you are in the presence of its corpse, you will continue to corrode. Wearing a hazmat suit will reduce the corrosion effect by 1 level. More protection on top of that (Like extra shielding, etc) may reduce the corrosion effect by another level.
The Contaminant is slow, and blind. It will not run after you. It is easily distracted. It will pause whenever it sees artefacts of human culture (TV ads, jingles, billboards, magazines, old photographs, etc). These things can keep it in a trance for a short while.
Directors commentary: I would put this in a large dungeon or wilderness area as a moving exclusion zone. As it wanders through the dungeon, it cuts off certain pathways and pushes the PC's to consider alternate routes. If the PC's are making a "milk run" in a safe path through the dungeon, this thing can make them to reconsider their plans or push them into travelling through areas they would normally avoid. It makes sure the place always feels alive and dangerous.
Contaminants are sometimes contained by government entities. Other times, they be used as guards for top-secret facilities or underground bases. Disposable agents in hazmat suits lure them into containment pods using human artefacts. Then they are let loose in the wilderness around the black site to keep out prying eyes. You may hear rumours of one lurking in the woods, or haunting an abandoned shopping mall, endlessly watching the ads on repeat.
Image credit: Eoin Mc Hugh | the ground itself is kind, black butter, 2014 black sheepskin, wax, steel, and mixed media 224 x 122 x 190 cm / 88.2 x 48 x 74.8 in