Per 
Item #: SCP-XXXX
Object Class: Euclid
Special Containment Procedures: Samples of SCP-XXXX are to be contained in the Foundation Center for Disease Control (Site-195-T), cryogenically frozen. Though SCP-XXXX is believed to be fully contained, and due to the Foundation possessing a sufficient sample size of SCP-XXXX in captivity, additional instances of SCP-XXXX found not inhabiting a human host are to be destroyed by incineration, preferably using a heat source of 1000°C and above, then by blasting the area with low-frequency sound waves, followed by high-strength rodenticide.
Host infected with SCP-XXXX are to be treated according to the severity of the contagion:
- Low-level infection (rat-to-human cell ratio of less than 30-100, no signs of facial abnormalities, no-to-minimal swelling of the throat, vocal frequency in traditional human range) is to be treated by luring the contaminant colony away from the host using one of its preferred food sources, then treating the host with a mixture of low-frequency sound waves, anti-bacterial agents and low-level rodenticide. The contaminant colony is then to be destroyed using the above-mentioned measures. The host is then to be kept monitored for signs of further infection for a period of no less than 72 hours. If the infection returns, the process is to be repeated. In the case that no further signs of infection occur, the former host is to be given class-B amnestics and released.
- High-level infection (rat-to-human cell ration of over 30-100, visible facial abnormalities, severe swelling of the throat, vocal frequency rising significantly above traditional human range) is to be treated by subjecting the host body to the above-mentioned measures directly until no further sign of SCP-XXXX infection remain. Due to the likely lethality of said measures, this method, though effective, should be used sparingly.
Description: SCP-XXXX is the designation given to a phenomena resembling a bacterial infection. The anomalous nature of SCP-XXXX stems from the nature of the individual microscopic organisms which comprise it- individual instances of SCP-XXXX bear a total, though much reduced in size, visual remembrance to the mammal Rattus norvegicus (brown rat).The Foundation has been unable to fully assess the extent of this resemblance beyond the visual- while SCP-XXXX does appear to display several physical similarities to the brown rat, such as requiring and desiring similar types of nourishment and shelter as well behavioral, such as an apparent need for the company of others of its species, in other ways it more resembles mundane single-cell organisms.
Instances of SCP-XXXX reproduce in a manner more similar to their bacteria-like nature- by infecting and spreading within host bodies, usually human. Once inhabiting a host body, SCP-XXXX will enter a brief germinating period (2-5 days) in the original infection point in the ears, followed by a rapid spreading to the rest of the head and eventually to the throat. The spreading of the infection is accompanied by a growing swelling and warping of the ears and eyes, an increase in the length and width of the nostrils and a sharpening of the incisor teeth the shedding of most molars, and is further accentuated with a great increase in the speed and coarseness of facial hair in the host. After a period of roughly 2-5 weeks, SCP-XXXX will eventually reach its terminus in the throat and will then proceed to warp the host's vocal cords in order to make them produce sound waves of an unusually high frequency.
It appears that these waves are the manner in which SCP-XXXX spreads and reproduces to other hosts- when sounds waves produced by SCP-XXXX reach an uncontaminated ear drum and cause damage to it (superficially similar to tinnitus) instances of SCP-XXXX will begin to manifest there, beginning the process anew with a new host. At this stage SCP-XXXX enters a near-dormant stage in the original host and ceases to spread.
Interestingly, despite instances of SCP-XXXX not possessing much in the way of biological similarities to the brown rat, they do exhibit several behavioral parallels, albiet in a circumstantial manner; SCP-XXXX infected hosts tend to favor foods that the brown rat finds desirable, such as bacon, chocolate and dried fruit despite any previous aversion to said foods, as well as a predilection to covering themselves in materials the brown rat tends to favor for nesting. This will often lead to unusual behavior on the part of the host, such as purchasing a large quantity of dental floss and using it to construct a nest-like bed. This change in behavior can assist in detecting SCP-XXXX infection while it is still treatable.
Notably, SCP-XXXX appears to posses a secondary, memetic element. Individuals infected with SCP-XXXX will universally fail to acknowledge its effects upon their persons, both physical and behavioral, and if questioned by others regarding said effects will attempt to dismiss them as minor or will attempt to justify them as intentional stylistic choices. The further the infection spreads, the more vehement the host tends to become in their denial of their situation, usually electing to eventually remove themselves from human company entirely in order to avoid commentary on their situation. Notably, SCP-XXXX infected hosts tend to get along very well with other infected individuals, even forming impromptu colonies if given the opportunity.
Addendum: [Optional additional paragraphs]
