Per 
Entity was discovered on the outskirts of Albequerque, New Mexico. Before death, entity vocalized a desire to destroy humanity.
Item #: SCP-XXXX
Object Class: Aquatic
Containment Class: Keter (SCP-XXXX-B is Thaumiel)
Special Containment Procedures: The continued containment of SCP-XXXX-A is enforced via the upkeep of SCP-XXXX-B. The average size and population of instances of SCP-XXXX-A is to be monitored and used accordingly in containment of SCP-XXXX-B.
SCP-XXXX-B is to be contained in an aquarium holding, at minimum, 2000 gallons of saltwater. A population of at least 50 crustaceans is to be maintained at all times. Uca minar is presently used for this purpose. A repository of at least 200 others is kept on-site if the containment population is depleted below 50. A marine biologist is to verify the health of the aquarium on a weekly basis.
SCP-XXXX-B is to be kept in the center of the aquarium by a truss arrangement capable of holding at least five tonnes. A shaft underneath the aquarium is to be maintained in the event that SCP-XXXX-B's becomes too massive to hold. This shaft is to be filled with gel capable of suspending SCP-XXXX-B until enough members of the Cetacea1 infraorder are killed for normal containment procedures to return.
SCP-XXXX-C is provided a standard humanoid containment cell at the same site where SCP-XXXX-B is contained. The containment cell for SCP-XXXX-C is built within 53 meters of SCP-XXXX-B, at SCP-XXXX-C's request. SCP-XXXX-C is to be provided with a diet of insects, in place of the standard humanoid diet.
Description: SCP-XXXX-A consists of fishes, Pinniped, Cetacea, and most other instances of marine life. When SCP-XXXX-B is not active, SCP-XXXX-A is capable of undergoing a rapid transformative process. The nature of this process is variable, but usually includes the development of new organs and an overall increase in body mass. Most instances of complex marine life (such as squids, octopi, and whales) are believed to be evolutionary descendants of SCP-XXXX-A who have undergone the process. Transformations have been known to introduce anomalous biology.
SCP-XXXX-B is a large ovoid artifact composed of prismarine, inscribed into a pyramidal base made out of stone resembling granite. The ovoid part of SCP-XXXX-B has a ring of turquoise gemstones encrusted around its widest point. Analysis of these gemstones is inconclusive; taking samples through traditional methods has proven impossible due to their toughness. The weight of SCP-XXXX-B fluctuates. It is believed, based on testimony from SCP-XXXX-C, that SCP-XXXX-B's weight is based on the current collective mass of all of SCP-XXXX-A.
At irregular intervals, SCP-XXXX-B will emit infrared radiation. According to SCP-XXXX-C, this is the start of an ill-documented process that prevents SCP-XXXX-A from undergoing transformations. In order to continue these emissions, SCP-XXXX-B must be surrounded by certain types of animals. Testing has concluded that crustaceans are the most effective in keeping SCP-XXXX-B active.
SCP-XXXX-C s a humanoid entity resembling a specimen of Delena cancerides2. The entity stands on its back four legs and manipulates its environment using the front four. SCP-XXXX-C does not sleep, but rather enters a semi-conscious meditative state for approximately 16 hours per day. SCP-XXXX-C claims to be the "designated guardian" of SCP-XXXX-B. Although it has since relinquished this duty to the SCP Foundation, it is kept on site due to its expertise in managing SCP-XXXX-B. SCP-XXXX-C has developed vocal cords and is capable of speaking in English.
Addendum XXXX-1: Recovery Log
Attempts to determine the Origin Point of SCP-1608 led to the discovery of SCP-XXXX. Triangulation of SCP-1608's early sightings led to a facility constructed within the Tonga Trench near New Zealand. The layout of the Origin Point implied that it was constructed before the Tonga Trench had expanded inwards.
Initial sampling of the Origin Point's exterior revealed it to be structurally similar to spider silk. An aperture analogous to an airlock was found to be installed on the facility's left side. When initial inspection personnel entered the airlock, they were jovially greeted by SCP-XXXX-C.
SCP-XXXX-C: Ah, top of the morning, gentlemen! Thank you for taking the time to stop by.
Δ12-1: Sir, permission to fire ?
Δ12-Cap: Randy, no. We don't fire unless they're aggressive.
SCP-XXXX-C: I'm glad you're here, because this reminds me of a serious problem. I was playing encirclement chess against myself some time ago, and I think I've lost a few pieces. You gentlemen seem to be in fine shape, could you help me find it?
Δ12-1: Do we help him find it, sir?
SCP-XXXX-C: Oh, sorry, that isn't the serious problem. My chess set is complete, and I have a tendency to forget things. Really, I'm about to die and the fish are about to revolt.
SCP-XXXX-C then led the personnel to the central room, where SCP-XXXX-B was stored atop a pedestal, surrounded by several spider egg sacs. When prompted, SCP-XXXX-C was able to take personnel to a series of containment cells holding dangerous instances of SCP-XXXX-A.
Addendum XXXX-2: Recovered Text
Most artifacts found at the Origin Point appear to have been deliberately destroyed. SCP-XXXX-C has asserted that his "ancestors" had made the choice to do so. The only recoverable item was a tablet found in a hidden compartment in the west wing of the Origin Point. SCP-XXXX-C was able to translate it.
The [ouroboros?] of our would began with [evolution/transformation]. [unknown] brought two to the world. The two [became/grew to] two [factions/species] and a war. We have won, but at a [penalty/death].
TODO: expand
Image sources: https://commons.wikimedia.org/wiki/File:Alindall_with_large_fish.jpg
