Item #: SCP-3809

Object Class: Euclid

Special Containment Procedures: SCP 3809 is currently contained within a population of cattle maintained on Foundation grounds and monitored by a combination of Foundation agents (Mobile Task Force Omega-V, the "Worm Wranglers") and autonomous aerial drones to prevent escape. Should an instance of SCP-3809 be discovered by a non-Foundation individual, it is to be dismissed as a forgery or hoax. Use of Class A amnesiacs is only authorized if the instance become sufficiently common knowledge to the general public.

Description: SCP-3809 is a parasitic worm, superficially identical to the common blood fluke (genus Schistosoma). Unlike a blood fluke, SCP-3809 matures inside the gut region of predatory birds, such as hawks, eagles, falcons, and owls. Instances of SCP-3809 hatch from eggs that are passed out in the excrement of their hosts and land on vegetation.

The eggs of SCP-3809 hatch when they are eaten, along with the vegetation on which they land, by a large herbivorous mammal. This host is hereafter designated SCP-3809-1. It is here that SCP-3809's anomalous properties manifest. Through an as yet not understood process, instances of SCP-3809-1 shrink over a period of eight to twelve hours to roughly 5 per cent of their natural dimensions. This size reduction seems to have no detrimental effect on SCP-3809-1's life, aside from making them more vulnerable to attack by predatory birds. When consumed by a predatory bird, SCP-3809 metamorphoses into its reproductive stage and lays eggs, which are once again passed out through the bird's excrement.

Instances of SCP-3809-1 do not experience a significantly decreased lifespan from their normal-sized counterparts, assuming they are not eaten by predators or otherwise killed. Their nutritional and metabolic needs are to scale with those of an organism of their original size, rather than those of species that are naturally small. It is unknown how long SCP-3809 can live inside of SCP-3809-1 before it needs to metamorphose, but the specimens at the Foundation have been observed to remain viable for years, and some instances of SCP-3809-1 have even lived long enough to die seemingly "natural" deaths.

Known instances of SCP-3809-1 include the following:
Domestic cow (Bos primigenius taurus)
Domestic sheep (Ovis aries)
Domestic goat (Capra aegagrus hircus)
White-tailed deer (Odocoileus virginianus)
Moose (Alces alces)
Mule deer (Odocoileus hemionus)
Domestic pig (Sus scrofa)
Domestic horse (Equus ferus caballus)

Addendum 01: Notes from experimental trials regarding the biological properties of SCP-2809

Trial 1: One (1) adult cow implanted with SCP-3809. Over subsequent period of 10 hours, 46 minutes, subject (hereafter designated SCP-3809-1) shrank to approximately one one-hundredth of its former size. Subject terminated.

Trial 2: One (1) adult pig implanted with SCP-3809. Over subsequent period of 6 hours 21 minutes, subject shrank to one fiftieth of its former size. Subject terminated. Conclusion reached that the larger the host, the longer it takes SCP-3809 to shrink it to a suitable size.

Trial 3 One (1) dead pig. No shrinking observed. Subject fed to five (5) turkey vultures, a scavenging bird common throughout North and South America. Subsequent stool samples indicate that the SCP-3809 was ingested and reproduced inside the vultures' digestive tracts. This proves that SCP-3809 can be transmitted even after its host has died.

Trial 4: One (1) albino laboratory mouse. Over subsequent period of [REDACTED], subject shrank to one twentieth of its former size, but died shortly afterwards. Subsequent necropsy revealed that SCP-3809 filled subject's entire body cavity, presumably killing it. This proves that host organisms of SCP-3809 need to be above a certain size, and that the shrinking reaction is not voluntary on behalf of SCP-3809.

Trial 5: One (1) adult ostrich, the largest living bird, implanted with SCP-3809. No shrinking observed. The implication is that SCP-3809's effects are limited to mammals.

Trial 6 One (1) adult pig, implanted with SCP-3809 and allowed to shrink. Subject subsequently fed to a house cat. Stool samples indicate that SCP-3809 did not lay eggs in the cat's digestive tract, suggesting that it only reproduces in the bodies of birds.

Addendum 02: Journal entries from ornithologist Dr. [REDACTED], detailing the discovery of SCP-3809.

7-22-[REDACTED]: The farmers in the area puzzle me. They report their livestock—their cattle, their sheep, even their horses —going missing, along with strangely aggressive behavior by predatory birds such as hawks and owls. Needless to say, as an expert on the subject, I find it highly doubtful that the two are related.

7-24-[REDACTED]: At long last, a possible clue. I've discovered an intact pellet from an great horned owl on the property of a local farmer. One of the same farmers, so it happens, who has reported his animals missing

(later, same day): As a man of science I am predisposed to approach everything I see with skepticism, but what I see now is seemingly solid proof of something that I thought was impossible. The contents of the pellet consist of the bones and wool of a sheep, only reduced to one-fiftieth their natural size. Is this a hoax, or some as yet unknown natural phenomenon? Maybe a DNA test will tell.

7-25-[REDACTED]: Figures. The folks back at the university didn't believe me. They don't want do the test. Guess I'll have to show them myself. Right now, heading to the farmer's market to pick up some fresh fruits and vegetables.

7-26-[REDACTED]: Heading back to the university today. Notice that my clothes are way more loose than they used to be.