Item #: SCP-5161
Object Class: Keter
Special Containment Procedures: Current means of containing SCP-5161 are hindered by its wide-spread nature. Containment is primarily managed via Foundation web-crawlers programmed to log SCP-5161 related symptoms reported within worldwide psychological/medical record databases.
Subjects experiencing the stages of SCP-5161 are to be investigated and if confirmed, to be taken into Foundation custody. As amnestic treatment has proven to prevent the ongoing effects of SCP-5161, subjects are to be treated appropriately and released.
Description: SCP-5161 is a reoccurring dream experienced by humans. An estimated 5000< cases of SCP-5161 have been reported annually, and no decisive connection between subjects has been determined. Dreams will last approximately three minutes in realtime, while subjects experiencing SCP-5161 will report roughly 3-6 hours passing from their own perspective.
In all instances, SCP-5161 involves the dreamer being completely submerged in a body of water, described as being yellow and murky in colouration, with no apparent bottom.
Subjects will experience SCP-5161 for 1-2 weeks daily, upon entering REM sleep. Following initial manifestation, SCP-5161 will become increasingly more lucid following each additional dream. During the 1-2 weeks period, dreams will become increasingly more realistic from the subject's perspective. Subjects will additionally experience anomalous phenomena associated with their dreams, often manifesting as small portions of salt water in their lungs and other objects materialising on their person, piercing the skin.
Throughout the 1-2 week manifestation period, subjects' dreams will incorporate the following changes and anomalous properties described in Document 5161-A.

DOCUMENT 5161-A

Stage #1: Subjects find themselves unable to move and will remain in the same spot while dreaming. Subjects may occasionally report feeling that they are not alone in the water.
Stage #2: Subjects become capable of controlling their movements while dreaming, although they may only swim in different directions. Subjects are unable to find the water's surface or a physical bottom no matter how long they spend swimming. While unlikely, subjects may report noticing small objects appearing to float in the distance. These objects are difficult to decipher, due to the murkiness of the water.
Stage #3: Subjects report experiencing physical stimuli during SCP-5161. Subjects will become capable of feeling the water around them, describing it to be fairly cold and dirty. Despite having no need to do so, subjects may feel the need to hold their breath, fearing they are running out of air. During this stage, subjects may report to have experienced piercing sensations on their skin.
Stage #4: Feelings similar to suffocation or choking will be experienced for the remainder of the dream. Subjects are highly likely to attempt swimming upwards to reach the surface.
Small amounts of yellow salt water will manifest in the subject's lungs. Subjects may notice multiple objects spread throughout the waters in the distance while swimming, similar to those described in Stage 2.
Stage #5: While attempting to swim towards the surface, subjects will notice an increasing number of objects floating in the distant waters. This number will increase in wherever area the subject is not presently watching. These will materialise perpetually closer towards the subject, until they are able to visibly identify them as metal fishhooks tied to fishing wire.
As subjects continue to swim, the number of fishhooks will increase in greater numbers and proximity towards them. Fishhooks will eventually start piercing the subject's body upon appearing close enough, and begin tugging the subject upwards. If subjects attempt to struggle, additional fishing lines will continue to appear, piercing their skin, and continue. This will usually result in the subject's body being almost completely engulfed in fishhooks. After a varying period of time, subjects that are still capable of sight will report seeing the water surface and sunlight above them.
If subjects are able to unhook themselves from these lines, they will awaken. Subjects will no longer experience SCP-5161 from then onwards.
Subjects unsuccessful in doing so before the dream's end will spontaneously dematerialise. After which, a thin layer of salt water will appear over the subject's body before falling.