In the 1960s, farmers throughout the United States found the corpses of animals, usually cattle, with vital organs removed, blood completely or partially drained, and sometimes external parts such as eyes or ears surgically removed. The most celebrated case involved a horse called Snippy. The phenomenon continued in the 1970s, reportedly spreading to Puerto Rico, Canada, Brazil, Bolivia, Sweden, Australia, Scotland and central Europe. Reports of unmarked helicopters and unidentified lights hovering over the mutilation sites, plus the reported absence of footprints around the remains, led investigators to connect the incidents with the UFO mystery. Some speculated that the livestock are airlifted, mutilated and then returned. An earlier incident of animal mutilation occurring with a connection to UFOs took place in 1897 in Le Roy, Kansas.

The Cattle Raiser’s Association, the Federal Bureau of Investigation (FBI) and local law enforcement agencies have had little success in solving the problem, although in 1975 the arrest in Colorado of the members of a nomadic satanic cult has led many researchers to conclude that the mutilations were carried out during black magic rituals. However, reports of mutilations continue to come in and the organisation, Project Stigma, exists for the express purpose of investigating this phenomenon. Its records show that many mutilated carcasses do not decompose as rapidly as they should. Moreover, in a large proportion of cases, predators and farmers’ dogs, while demonstrating curiosity, do not go within close range of the victims.

Trevor James Constable attributes the incidents to biological UFOs, which he calls invisible critters, denizens of the atmospheric regions known as Etheria.