 SCP-366 refers to a human endoparasite of unknown, possibly extraterrestrial origin. Upon introduction of SCP-366 over to a male host via inhalation or ingestion, specimens travel through the body to settle in the testes. Larva developed in male hosts are transmitted to female hosts through ejaculation. Larva transmitted in this manner attached to the lining of the uterus, to grow to their adult form. After three to six weeks, the remaining adult specimen leaves the host in an ABE-366 event.