I read the first series from that on the wiki a while ago, and recently went back and read Five Five Five Five Five. I absolutely love the ideas behind antimemetics, this kind of eldritch horror and how to deal with it. I was slightly disappointed towards the end,
ending spoiler
the SCP seems to be portrayed as existing in conceptual space, an antimeme that prevents information about it existing while somehow being a self-sustaining idea? It's referred to as a "meme complex" on the 3125 page. But at the end it's portrayed more like a god acting in mysterious way, talking to the protagonist, existing in a way where it can be harmed with a gun. Not killed, but actually permanently injured?
Still a great story either way, and a good read for free, I had no idea it was published independently, have look into it!