A cognitohazard is a artificial pattern, usually visual, that actually hacks the human brain causing harmful psychological effects to anyone who sees it.
The initial idea came from the author David Langford, from his story BLIT: http://www.infinityplus.co.uk/stories/blit.htm, though the idea of an image too dangerous to look at appears in many fictional works (Including a lot of SCP entries)

I thought I’d write up the idea for my Khonshu Alpha #Dungeon23 project. It’s Cepheus/Traveller compatible, so it should work in any 2d6 setting.
I’ll probably write up an expanded version of this for the Cepheus Journal.
Creating a Cognitohazard
To create a cognitohazard, you need to have the Neuroscience skill, and access to an expert AI system of at least TL 15. Once the cognitohazard is created with a successful Neuroscience roll, it can easily be copied, even by equipment of a much lower tech level. A TL 7 copy machine can produce hundreds of copies of a cognitohazard, given an original. Images and videos of cognitohazards can also be spread easily through data networks.
To create a cognitohazard in a still image, the difficulty is 11+
To create a cognitohazard in a video clip, the difficulty is 9+
Each cognitohazard has a Intensity. This is the difficulty number that a target has to beat with an END roll to avoid the full effects of the cognitohazard.
Cognitohazards are species-specific. A cognitohazard designed for humans will not work on any alien species. I’m assuming that the cognitohazard is visual, though it could also be a sound, or even a smell.
Known Cognitohazards
The Big Sleep
Intensity: 8+
Puts the brain in a comatose state, rendering the target alive but unconscious.
Can be undone with a Medical 10+ roll
Gasper
Intensity: 8+
Target’s lungs will no longer operate. Targets will take D6 damage per round.
Heartstopper
Intensity: 8+
The target’s heart stops. Death in D3 rounds.
Lethe
Intensity: 8+
Target loses all memories, permamently. If target makes their END roll the memory loss is temporary – D6 hours
Freeze Tag
Intensity: 10+
The target is paralyzed. They can still hear and see normally. Can be undone with a Medical 8+ roll
Gullible George
Intensity: 10+
Disables the target’s judgement for approximately 5 minutes. Anything the target hears in those five minutes, they will believe with an unshakable faith.
Dead Man Walking
Intensity: 8+
Target will suffer from Cotard’s Syndrome, and will be convinced they are dead, despite any evidence.
Rage-Monkey
Intensity: 10+
The target will experience uncontrollable anger. They will immediately attack anyone who gets in their way.
Scaredy Cat
Intensity: 8+
Target suffers from crippling fear, and immediately flees the area.
Twitch
Intensity: 10+
Target suffers an epileptic fit, lasting 10 minutes
Gear
Blinders (TL 14) 4500 Cr
Augmented Reality goggles designed to filter out all known cognitohazards. All cognitohazards will appear as scrambled images in the user’s sight. Some models will identify the nature of the cognitohazard.
Graffiti Bot (TL 9)
A flying drone with a paint sprayer. It can be programmed with a cognitohazard pattern and programmed to spray an image on any surface. Alternately, they can be programmed to deface existing cognitohazards.
Small (two images) 50,000 Cr
Large (ten images) 95,000 Cr
Effects on a campaign setting
Cognitohazards are incredibly dangerous. Once created, a cognitohazard can be copied infinitely and used over and over again. A cognitohazard let loose in an information network could conceivably destroy a civilization.
Cognitohazards are usually illegal in most societies, often treated as the information equivalent of biological weaponry.
In a spacefaring settings, worlds where cognitohazards appear might be quarantined. All travel to and from the surface is prohibited, and all electronic communications are jammed until the threat is dealt with. Governments might resort to extreme measures to prevent the spread of a cognitohazard.
For another angle on this great idea you might enjoy The Gardens of Ynn, where the Idea of Thorns was created somehow ages ago. This destroyed the civilisation, leaving a particular technological relic decaying and dangerous for anyone follhardy enough to explore. Naturally, they run the risk of seeing and being contaminated by the Idea, which drives them mad https://www.drivethrurpg.com/product/237544/The-Gardens-Of-Ynn
LikeLiked by 1 person
Technically the triggering video depicted in Serenity could be considered a cognitohazard
LikeLiked by 1 person
Ynn is great, and as you point out, a really interesting fantasy spin on the same idea.
LikeLike