How can I find natural occurances?

Polycephaly is the condition of having more than one head. By far the most common use is in relation to the anatomical head, though the word has also been used for other meanings of "head". The term is derived from the stems poly- meaning 'many' and kephal- meaning "head", and encompasses bicephaly and dicephaly (both referring to two-headedness). A variation is an animal born with two faces on a single head, a condition known as diprosopus. In medical terms these are all congenital cephalic disorders.