Lernaean Hydra
Polycephalic or multi-headed animals are rare in biology, but commonly feature in mythology and heraldry. Multi-headed dragons, like the 8-headed Orochi and 3-headed Trisiras above, are a common motif in comparative mythology. For instance, multi-headed dragons in Greek mythology include the 9-headed Lernaean Hydra and the 100-headed Ladon, both slain by Heracles.