Polycephaly
![Heracles and the Lernaean Hydra by Gustave Moreau: The Hydra is perhaps the best known mythological multi-headed animal, also popularised in many fantasy settings.](/Images/godic/202502/16/Gustave_Moreau_0030422.jpg")
![The Tocci brothers as young boys in 1881.](/Images/godic/202502/16/Tocci-Zwillinge_1881-2-MJ0423.jpg")
![Drawing of the eighteenth century Boy of Bengal, affected by craniopagus parasiticus.](/Images/godic/202502/16/TwoHeadedBoyofBengal0423.jpeg")
![Skeletal structure in a case of dicephalus parapagus dipus. From: Hirst & Piersol, 1893.](/Images/godic/202502/16/Dicephalus_dibrachius_diauchenos0423.jpg")
Polycephaly is the condition of having more than one head. The term is derived from the Greek stems poly- (Greek: "πολύ") meaning "multiple" and kephalē- (Greek: "κεφάλη") meaning "head". A polycephalic organism may be thought of as one being with a supernumerary body part, or as two or more beings with a shared body.