List of legendary creatures (O) explained

1. Obake (Japanese) – Shapeshifting spirits
2. Obariyon (Japanese) – Spook which rides piggyback on a human victim and becomes unbearably heavy
3. Obayifo (Ashanti) – Vampiric possession spirit
4. Obia (West Africa) – Gigantic animal that serves witches
5. Oceanid (Greek) – Nymph daughters of Oceanus
6. Odei (Basque) – Storm spirit
7. Odin (Norse mythology) – King of Asgard
8. Odmience (Slavic) – Changeling
9. Og (Jewish) – Giant king of the Amorites
10. Ogopogo (Canadian) Canadian Lake Monster
11. Ogun (Nigeria) – Iron god for the Yoruba people (South Western Nigeria)
12. Ogre (Medieval folklore) – Large, grotesque humanoid
13. Oiwa (Japanese) – Ghost of a woman with a distorted face who was murdered by her husband
14. Ojáncanu (Cantabrian) – Giant cyclops who embodies evil.
15. Ōkami (Japanese) – Spirit wolf of powerful
16. Okiku (Japanese) – Spirit of a plate-counting servant girl, associated with the "Okiku-Mushi" worm
17. Ōkubi (Japanese) – Death spirit
18. Okuri-inu (Japanese) – Dog or wolf that follows travelers at night, similar to the Black dog of English folklore
19. Ole-Higue (Guyanese) – Vampiric hag who takes the form of a fireball at night
20. Oluru, Leopard Warrior ((Tanzanian))-A leopard from Tanzania...
21. Ōmukade (Japanese) – Giant, human-eating centipede that lives in the mountains
22. Oni (Japanese) – Large, grotesque humanoid demon, usually having red skin and horns
23. Onibi (Japanese) – Spectral fire
24. Onmoraki (Japanese) – Bird-demon created from the spirits of freshly dead corpses
25. Onocentaur (Medieval Bestiaries) – Human-donkey hybrid
26. Onoskelis (Greek) – Shapeshifting demon
27. Onryō (Japanese) – Vengeful ghost that manifests in a physical rather than a spectral form
28. Onza (Aztec and Latin American folklore) – Wild cat, possibly a subspecies of cougar
29. Oozlum bird (Unknown origin) – Bird that flies backwards
30. Ophiotaurus (Greek) – Bull-serpent hybrid
31. Opinicus (Heraldic) – Lion-eagle hybrid, similar to a griffin, but with leonine forelimbs
32. Orang Bunian (Malay) – Forest spirit
33. Orang Minyak (Malay) – Spectral rapist
34. Ördög (Hungarian) – Shapeshifting demon
35. Oread (Greek) – Mountain nymph
36. Ork (Tyrolean) – Little people and house spirits
37. Orobas (European) – Horse-headed, honest oracle classed as a demon
38. Orphan Bird (Medieval Bestiaries) – Peacock-eagle-swan-crane hybrid
39. Orthrus (Greek) – Two-headed dog
40. Osiris (Hellenized) – God of the dead and the judge of the underworld
41. Oshun (Nigeria) – God of love and fertility
42. Otso (Finnish) – Bear spirit
43. Ouroboros (Worldwide) – Mystic serpent/dragon that eats its own tail
44. Ovinnik (Slavic) – Malevolent threshing house spirit
45. Owlman (Cornish) – Owl-like humanoid