Per 
An instance of SCP-XXXX-2 emerging from a swamp
Item #: SCP-XXXX
Object Class: Keter
Special Containment Procedures: Any reports of wild instances of SCP-XXXX are to be investigated by MTF Xi-18 ("Jack Frost"). Any witnesses are to be given amnestics determined by their level of contact, and any formal investigations by non-foundation personell are to be misdirected and chalked up to local urban legends. Instances of SCP-XXXX-2 are to be terminated, and bodies of any SCP-XXXX-2 victims are to be removed from the area and returned to families under the guise of accidental drowning.
A single instance of SCP-XXXX-2 is to be kept inside a 5m x 5m x 5m containment cell outfitted with a large pool in the center, and equipped with a remote-activated barrier covering the pool that can be closed or opened from the observation area. The pool will be filled with a mixture of swamp water and mud to keep the water as opaque as possible. Any time the water begins to clear, more mud and swamp water is to be added via remote pump system to avoid a migration event. At least two guards are to be posted to the door, equipped with liquid nitrogen-based weaponry in case of a breach. All on-site personnel are to be notified that any glowing blue lights are instances of SCP-XXXX-1, and are to be ignored.
Description: SCP-XXXX consists of two separate entities that seem to share a commensal relationship. Neither entity have been seen separated, and instances of SCP-XXXX-1 always appear or disappear with the creation or destruction of SCP-XXXX-2 instances. SCP-XXXX only appears in and around murky, opaque bodies of water no smaller than 3m in diameter. If the body of water becomes too clear or too small, SCP-XXXX will migrate to a different body of water meeting the same criteria. Migration events are instantaneous, and appears to have no upper limit in terms of distance from the original body of water. New SCP-XXXX instances can also appear in any body of water meeting the criteria at any time, so long as the body of water is not being directly observed by living organisms.
SCP-XXXX-1 consists of a species of insect that appears to be structurally similar to the Lampyridae (firefly) family. It emits a bright, light blue light at all times which can be seen even when under other light sources. It's anomalous nature resides in it's ability to teleport short distances, which it uses to avoid contact with living organisms that approach closer than 1 meter. No attempts to approach SCP-XXXX-1 have succeeded, making study of it very difficult. SCP-XXXX-1 instances only exist near bodies of water containing SCP-XXXX-2 instances, and appear to be bound to them through some unknown means. SCP-XXXX-1 instances are shown to migrate along with the SCP-XXXX-2 they are connected to, and only perish when their corresponding SCP-XXXX-2 instance does. No other methods of termination have been found to affect SCP-XXXX-1
SCP-XXXX-1's behaviors typically focus on luring victims towards SCP-XXXX-2 by teleporting outside of a victim's reach and guiding them towards SCP-XXXX-2. SCP-XXXX-1 does not require sustenance or rest, and appears to exist only to lure victims towards instances of SCP-XXXX-2. However, observation has shown that SCP-XXXX-1 and SCP-XXXX-2 are two unrelated species, and the reasoning behind SCP-XXXX-1's behavior is currently unknown.
SCP-XXXX-2 is a humanoid creature that appears inside any body of water larger than 3m that is too opaque to see through. Chemical tests have shown that it's body is made of a mixture of mud, and human bones, hair, blood, and bile. DNA tests have shown that mature instances of SCP-XXXX-2's mixture is made of components of it's past victims, while younger instances show no identifiable DNA match. While SCP-XXXX-2 doesn't appear to feed, it does show hunting behaviors towards any living creature that enters it's territory. Tests have shown that it prefers humans, but will attack other creatures such as mice, frogs, fish, horses, and even one instance of a male African Elephant.
SCP-XXXX-2 will begin it's hunting behavior by stalking any creature that enters the body of water it inhabits. It will not attack or make itself known, but it may occasionally brush against any part of the victim in the water. Should the victim leave the water at this time, there is approximately a 63% chance that SCP-XXXX-2 will return to a docile state. However, some SCP-XXXX-2 instances migrate to other bodies of water closer to the subject, "stalking" them for upwards of 15 years. Should the victim remain in the water, SCP-XXXX-2 will begin it's attack.
SCP-XXXX-2 attacks by grabbing the victim and pulling them under the water completely. It then proceeds to [REDACTED], before grabbing the victim's throat and squeezing it until the victim's windpipe crushes and the victim drowns. SCP-XXXX-2 appears to possess strength far greater than a normal human, and any attacks made against it appear to do no damage, as it's body immediately reforms any damage it might receive.
The only thing that appears capable of stopping SCP-XXXX-2 is flash freezing. Although SCP-XXXX-2 has been found in water below -19 degrees Celsius, it appears that freezing instances of SCP-XXXX-2 quickly and at very low temperatures is enough to freeze it's body, rendering it terminated. As such, MTF Xi-18 and guards posted to SCP-XXXX-2 have been equipped with weaponry designed for the dispensing of liquid nitrogen, which has proven effective.
