Placeholder, will give feedback soon!
Edit: Strap in, here we go!
The first and foremost problem I can see is that, simply put, it has too many powers. It can make portals, shapeshift, generate monsters, regenerate, have an impenetrable shell, bite through metal, flight, intelligence, super strength and speed, cognitohazards in its speech, its monsters can pass through walls, and is seemingly immune to everything the Foundation throws at it.
Shave off about ten of those abilities, and then you have a good base to work with. I would strongly suggest heading over to the Ideas and Brainstorming forum, and work on developing the concept there. Right now, it just seems like your standard "Super-mega-powerful-hyper-overkill-double-keter" anomaly, which really isn't fun for anyone to read. We get it, it's powerful and dangerous and cool. But is it interesting? Remember, an SCP article isn't just a faux scientific document, it's a story disguised as one.
There are a few threads here that you could work off of. The thing makes portals, but never goes in them, and seems at odds with what comes out. That's good, that's a concept that could go somewhere.
A tip: You're supposed to make "Item #", "Special Containment Procedures" and "Description" bold. You can do this by placing two asterisks on either side of them, like this:
**Item #:**
which gives you:
Item #:
A few minor nitpicks, now:
- Work on developing your clinical tone, it's what separates SCP from just normal creepypasta.
- Break up your paragraphs a bit, they are unorganized and just appear as huge walls of text.
- It really shouldn't be SCP-XXXX-UF, it should be SCP-XXXX-1. That's the standard format for sub-anomalies.
- Remember to check your spelling and grammar!
Good luck!