SCP Foundation

have a 10 (ten) cm thick layer of lead

You don't have to include the "(ten)" unless precision is of the utmost importance. Is it critical to containment that it be precisely 10cm? If the answer is no, then just 10cm is fine.

predict future events that will occur within 40 seconds

This is redundant. "Predict events that will occur" is fine. You cannot predict past events since they already happened.

The entity claims itself to be the ruler of all things that could have been and can alter its shape into a random combination of human or even non-human traits that could have been

This sentence should end "non-human traits". It's awkward and non-clinical phrasing.

While SCP-XXXX doesn't require food, it still requires a form of sustenance found in the form of what it describes simply as "Could-have-beens".

Wording. The "form of" used twice within a few words is awkward; I would encourage you to revise this whole paragraph to be more succinct. This is the part of your skip where you really start to drop the ball on your clinical tone.

When given an aging subject, SCP-XXXX will begin to distort space-time inside of the cell

Are you sure? This would likely be highly destructive to containment. Consider 'less is more' here.

although their form will flicker between various states of what the subject could have been.

I understand what you're going for and it's very good that you're reinforcing the theme of your article, but it's just not clinical at all. Abstract is tough to do in a clinical way for the best of us. You may want to use language about possible permutations, or something about probability sets, or any number of things. But really vague language in general in this article needs to be reigned in a lot inside of the Containment and Description block.

Current form appears to have its entire outer surface coated in a dark water-like substance that appears to be directly taken from the abyssopelagic layer of the ocean.

Water in that layer isn't different water; there's just absolutely no light. It seems like maybe you are trying to convey in your article that the SCP is a humanoid popout of the abyssal layer of the ocean. Strongly consider revising the language here. I think this is another case where your attempt to be abstract is getting in your way.

2. This form is the form that SCP-XXXX was discovered in. It took the shape of a bipedal bat-like creature that was covered in a metallic material that was identified to be an alloy of bismuth, antimony and mercury. This form featured prominent incisors that produced a form of ████ that, when combined with ███, will create a drink that gives the drinker intense feelings of regret for any past actions that have induced feelings of ████ within the subject.

This whole paragraph is all over the place. Consider breaking this up.

While SCP-XXXX has proven to be rather amicable to Foundation staff, the entity has a rather aloof personality.

Wording. Rather/rather twice in close proximity.

and after approximately ten (10) days after a lack of sustenance, the entity will become hostile towards Foundation

Why is it only fed every six months then? Why is it fed at all?

Basically, I was studying the various tablets found in around SCP-XXXX's coffin. And basically I have come across more material.

Wording. Basically/basically in close proximity.