SCP Foundation

A cave-dwelling hominid species with several unusual (albeit nonanomalous) anatomical features, formerly inhabiting a wide range in the Mediterranean but currently limited to isolated areas of inland Sardinia. Their main anomalous effect is some kind of mind-affecting/memetic property that allows individuals to transfer images/ideas/emotions into the minds of other animals, including members of their own species, within a wide range. In prehistory/early antiquity this resulted in their physical appearance appearing frequently in the minds of humans inhabiting the Mediterranean, and thus they became the basis for many early myths about "wild men".

Ultimately as their range decreased (maybe due to Foundation influence), their unnerving image became nothing more than a distant folk memory; however, the uncanny similarities between so many costumed folk characters of the region would be directly attributed to this anomalous memory (with Sardinian costumes - in particular the mamuthones, merdules and colonganos - being the most accurate). Perhaps this even resulted in modern-day fictional characters bearing similarities to that archetype (Cybermen, Uruk-Hai, etc)?

The Foundation would at some point have established a facility in Sardinia to study the creatures. The twist would follow the discovery that some members of the species have picked up the Sardinian language - ultimately they are discovered to be both more intelligent and more cooperative than initally assumed, and once trust has been established, an interview is carefully arranged. They would eventually explain the purpose of their strange telepathy, and I could see two possible answers:

1. A communication method - something that allowed for cooperative telepathic conversations between widely distributed populations of both their species and humans, but which humans interpreted as intimidating taunts from demons, resulting in them shunning and demonising the species and ruining what could've been a peaceful cooperative relationship. (oh humanity, never change)
2. A defense mechanism - they intentionally make themselves appear scary, but only in order to defend themselves against both violent humans and other predators. Said predators are only briefly referenced, but are implied to be far worse horrors that humanity is lucky not to have encountered ("nothing is scarier" and all that).

Okay so, I immediately like the idea of a hive mind community… that incorporates others. I think that is cool. Like, not full on hivemind, but a subconscious sharing of ideas. I imagine that if everyone's thoughts can be perceived by everyone, you slowly homogenize and become the same. It would be really cool to see people brush up against this experience. I think there is a lot of story potential there.

I mean, imagine this as well:

Imagine if people hadn't gotten solid evidence on these guys, but because they have a wide area of effect, people experience a weird "disassociating" in certain, say, mountain passes. You can then record the confused brief "merging of consciousnesses" by unwilling patrons from across the eras, combined with some "invading thoughts" of wild, strange looking men. You could (as it seems you have already planned) link these experiences to the cultural archetype of "wild men".

But, what I'm not seeing is the connection between the themes of "wild men" and such a communicative anomaly. I think you're gonna have to pull off some fun, innovative concept melding. Perhaps something a bit more conceptual than the anomaly having evolved as a purely communicative measure on the part of the "wild men".

Also, though this might be personal taste, I think this story might be better told without ever actually talking to the "wild men". Keeping them mysterious and otherly might add an air of, ehh, well I guess the word is mystique but it feels awkward to use mystique and mysterious in the same sentence. It would be nice if maybe the final addendum had maybe the first real confirmed sighting of them, but it wasn't by the Foundation, and no communication was established. I think that, if you played your cards right, that could be a very intriguing ending. But I can only see an interview with them playing like straight exposition, and I don't think we want straight exposition.

I don't have a closer for this… I think it'll be interesting to play with the idea of "cultural zeitgeist" and those ideas that somehow persist between cultures (like how almost every culture has a form of dragon) through the lens of a literal shared consciousness. Like, play with the metaphor by making it a reality. That, my good sir or madam or neither or both, sounds like a really fun article.