I don't normally deal with specific creatures, but I thought I'd put up a system neutral creature for use in anybodies horror games. The Peripheral Terrors.
Peripheral Terrors are a lanky, fast moving humanoid with a dull grey skin. What exactly they look like is not known... as they can only be seen in your peripheral vision.
Turning to look at a Peripheral Terror means you can no longer see it, asking you to wonder if it was ever there at all. Terrors appear to be incorporeal, in so far as they can only be interacted with while in your peripheral vision, flooding a hallway you are certain they are in with flame,arrows or bullets will not harm them. They leave no footprints, yet cannot go through walls or closed doors or windows. They do however have the ability to manipulate, pick up and move objects (or harm people), though they are always quite discreet to avoid doing anything obvious (such as walking around holding something you can see when you turn to them).
Peripheral Terrors appear to be skilled climbers, able to scale sheer surfaces. They also appear to be quite adept at picking locks, disabling security systems and hiding from someones peripheral view behind objects.
These creatures will frequently be seen out of the corner of ones eye, standing in front of oblivious individuals, doing something with their mouth to the individuals face. Exactly what is being done cannot be seen.
Over time the affected individual will appear to have their face covered in small writhing worms in your peripheral vision, but again, you will see nothing straight on. The targeted individual will start to grow sickly with wasting diseases, their mind will begin to lose memories, at points they will black out and not remember actions they have taken. They end up both insane and infirm unless the worms are removed from on (and inside) their face.
Peripheral Terrors are not invisible, so spells or electronic devices to see the unseen will not locate them... unless you see the device through the corner of your eye, where it will clearly show them (ie, motion detectors), until you once more look at your device straight on..and it will clearly show they were not there. If a security system (such as cameras or motion detectors) leaves hard copy proof (such as log files or photos) the Peripherals will also not appear, unless seen through your peripheral vision.
The exact goals of the Peripheral Terrors are inscrutable, but they are filled with malice. And they do not like being investigated or discovered, they can and will lash out to cause your death..usually through unfortunate but scientifically plausible accidents. The Terror's may act alone, or they may travel in packs.. no one knows how large these packs get..some say they are a rare creature, some say thousands..some say they may outnumber regular people.
Peripheral Terror's will fit into any fantasy, supernatural horror or science fiction game.
Welcome to your doom
8 hours ago