Two Headed Snakes

- In July 2009, a pair of dicephalic twins were born in Indonesia with two hearts, and sharing all other internal organs.
Craniopagus parasiticus - parasitic twin head with an undeveloped (or underdeveloped) body attached to the head of a developed twin:
- In 1783, the "Two-Headed Boy of Bengal" was born in India; the second head was joined roughly upside-down on top of the developed twin's head. The boy survived until 1787 and was killed by snakebite.
- In 2003, Rebeca Martinez was born in the Dominican Republic with an extra head but died 7 hours after surgery at the age of 8 weeks.