Noting some inaccuracies and misinformation here.
has a memetic field that causes people who get too close to hallucinate and go into cardiac arrest.
That's not how memetics work. Maybe take a look at the Understanding Memetics page for more explanation—basically, a memetic effect relies on the transfer of some sort of information. It's not just a general thing that emanates in an aura; that's a mind-affecting effect typically.
Also, as a general note, we already have a lot of SCPs that run the "hallucinate, and then die" gambit. Take a look at the articles tagged with "hallucination". Personally, I recommend using a different track, since the "you go crazy and then have a heart attack" route is done many, many times by new authors, typically resulting in downvotes and deletions because the audience has already seen that sort of stuff a lot and is no longer interested in it (regardless of how many older articles from 8-10 years ago use that premise).
thinking that it’s from say maybe the early 1700’s and the hallusinations are pieces of it’s past from being locked up and killed in a horrific way.
Seems like the plotline for a lot of franchise horror games. This might be workable as a tale, but comes off as on the overly predictable and trite side for an SCP article. I personally recommend that you try something else, unless you can come up with something extremely unique and novel so people don't just make comparisons like "oh, it's just like that area/monster/story from Silent Hill" or the like.
