SCP-1000 is a nocturnal, omnivorous ape, classified in the Hominini branch along with genera Pan and Homo. Adults range in size from 1.5 to 3 m (5 to 10 ft) in height, and weigh between 90 and 270 kg (200 - 600 lbs). They have grey, brown, black, red, and occasionally white fur. They possess large eyes with good vision, a pronounced brow ridge, and a sagittal crest on the forehead similar to that of the gorilla, but present in both sexes. Their intelligence is on par with that of Pan troglodytes (the common chimpanzee). SCP-1000 evolved alongside Homo sapiens, existing contemporaneously with proto-humans and humans in large numbers until 10,000-15,000 years ago, when an extinction event eliminated all but 1-5% of their population. This event was triggered by SCP-1000 contracting an anomalous "pseudo-disease" classified as SCP-1000-f1. This disease is passed on at the genetic level and affects every present-day instance of SCP-1000. The majority of SCP-1000 instances are born immune to the effect; those who are not born immune quickly die. The effect of SCP-1000-f1 is as follows: Any hominid (including humans, chimpanzees, bonobos, and non-immune instances of SCP-1000) that directly or indirectly observes any instance of SCP-1000 has a minimum 2% chance of being instantly killed through anomalous means via permanent cessation of brain function. This percentage is cumulative, and the longer a human views SCP-1000, the higher the chance of instantaneous death increases, at a rate of +1% chance per 20 minutes of viewing. This effect varies between individual members of SCP-1000's species, with some individuals carrying a 'death chance' of 90%. The effect is also produced by dead individuals, though small fur samples do not exhibit the effect.