Endometriosis was the Furon who was responsible for making clone body molds on the Fourth Ring of Furon, and who made a major breakthrough in cloning technology. He was a lecherous Furon with an Italian accent who considered cloning to be an art form, and loved Earth Women. Unfortunately, Endometriosis' boss, Helicobacter, an eccentric vivisectionist, kept the prime specimens for his own experimentation. After Crypto stole Helicobater's specimens, Endometriosis was able to take the request of creating a new body for Orthopox (in order to get past palace security). Inspired, both Pox and Endometriosis wanted Helicobater dead. After Helicobacter's death, Endometriosis celebrated his death and created a new body for Pox. Unfortunately, he used the wrong mold and created "Monkey Pox". Before he could correct the error, Endometriosis' cloning molds were destroyed and Pox and Crypto were forced to flee.
- Endometriosis was voiced by Robin Atkin Downes, who also voiced Ivan Oranchov in Destroy All Humans! 2.