It is doesn’t happen very often, but every once in a while an animal is born with two heads. These weird two headed animals usually don’t seem to live very long, but while they are alive they sure are a fascinating to look at. Bicephalic or tricephalic animals are the only type of multi-headed creatures seen in the real world and are formed by the same process as conjoined twins: they result from the secondary union of two originally separate monozygotic embryonic disks.