Anything mythological is related to a fable, legend, or other traditional story. As much as some of us don’t want to admit it, mythological creatures aren't real.
A mythology is a collection of traditional stories about characters such as deities, heroes, and fanciful creatures. Anything related to a mythology is mythological. Creatures such as unicorns and the Kraken are mythological, as are elves, dragons, and goblins. This word applies to beings and events that can't be verified by facts. Something mythological can also be described as mythic, mythical, or mythologic.