Class- Keter
Containment Procidure: SCP-XXXX is to be contained within a 10mx10mx5m subterranean vault of reinforced concrete encased in lead, immursed mercury, and with a single exit stairwell equipped with demolition charges. On the orders of O5-[Redacted], in the event of containment breach the charges are to be detonated and negotiations attempted with SPC-XXXX to remain in or return to the vault. In the event of negotiation failure the on-site warhead is to be detonated within 10 hours of containment breach, or immediately on SCP-XXXX successfully fleeing the vault. Only D-class personel are permitted to enter the vault to converse with SCP-XXXX or bring an approved item to it due to events of [Redacted] (see addendum 2).

SCP-XXXX was discovered buried under an ancient landslide in the [Redacted] province of [Redacted], by agent [Redacted]. The agent received a note believed to have originated from the individual refered to as "Nobody" warning that an unspecified interest group was closing in on SCP-XXXX's location with an ultimate goal of weaponizing SCP-XXXX-1. SCP-XXXX consists of 2 parts, SCP-XXXX-1 is a symbiotic fungus like entity of unknown origin. SCP-XXXX-2 (henceforth known as "Subject") appears to be a human female of apparently 20 years of age, but does not share mitochondrial DNA with any known living human. Subject was found to be completely illiterate and spoke a handful of words believed to be Neolithic in origin when first contacted Initial IQ was estimated low 60s. Since containment at site [Redacted] Subject has become fully fluent in 13 modern languages and fully literate in 15. Subsequent tests revealed an IQ in excess of 180, (see addendum 2).

Subject's entire left arm and a considerable portion of torso appear to have been overtaken and replaced by SCP-XXXX-1 which has modified itself to preform several organ functions. Such adaptive symbiotic properties have become a key point of ongoing research (see addendum 3).

SCP-XXXX-1 has proven capable of extracting energy from materials thought incapable of supplying sustenance, including various metals and stones. Material density slows the process linearly, Mercury is the only known toxin to SCP-XXXX-1.