Item #: SCP-4291

Object Class: Euclid

Special Containment Procedures: The location and pressure associated with SCP-4291 make relocation impossible. Therefore, containment measures are to focus on mitigating the spread of SCP-4291-1 instances. MTF-Gamma-19 ("Scuba cum Laude") is to be deployed during seasonal events in order to contain SCP-4291-1 instances.

Description: SCP-4291 is a Russian submarine sunk off the coast of Margate in the UK. Precise identification of the make and model is hindered by the anomalous growth coral around the base of SCP-4291 and through the hull. While superficially resembling Acropora hyacinthus, this coral appears to be endemic to cooler ambient temperatures and presents local deformation resistance equivalent to the Rockwell C scale. These growths are to be considered part of SCP-4291 and have grown over the entrance hatch and torpedo bay doors. This, combined with the position of SCP-4291 being partially buried (estimated 40% of the total length) in a local rock formation, makes entry to the interior of SCP-4291 impossible. The rock outcropping is likely the remnant of two larger boulders, and is covered in Acropora humilis, which presents no anomalous properties other than surviving in colder ambient temperatures.

The bow of SCP-4291 has been breached and lifted clear of local rocks with a yaw of approximately 40 degrees; however, it is covered entirely by coral tissue growth. It is unknown if this breach is the cause of SCP-4291 sinking or if it occurred afterwards. Sonar scans and physical probes of SCP-4291's bow port have failed due to unexpected calcification of the coral in response to stimulation.

SCP-4291 undergoes a periodic effect determined by global ocean current patterns. Thermohaline circulation bringing warmer water temperatures occurs once per year in the spring and correlates strongly with these effects. During this seasonal pattern, the girth of SCP-4291 will increase 30% as it is engorged with SCP-4291-1. After this, SCP-4291 will retain its new size for one week on average, after which it will expel approximately 60 instances of SCP-4291-1 through the bow as the coral tissue growth recedes temporarily. After a refractory period of 2 weeks, the cycle will repeat three times.

SCP-4291-1 appear to be the former crew of SCP-4291. They are dressed in standard attire issued to the Voyenno-Мorskoi Flotin in the 1970-1971 period. While the corpses present no anomalous effects outside of their relationship to SCP-4291, dental and DNA records do not match any known Foundation databases.

SCP-4291-1 are appropriately buoyant. After their expulsion from SCP-4291, they will float at neutral buoyancy until putrification.

Addendum 4291.01: Discovery Report

SCP-4291 was uncovered by Foundation dive crews after local reports from Margate, UK, indicated seamen washing up on shore.