Well, it's possible to fashion ones own metaphysical appearance to mimic something that is in fact "not real" and its also possible that there could be beings that would be similar to such mythical creatures.

There are also ways to force a person to see what they want to see, rather than what truly "is." It seems to be a popular defense mechanism for spirits (apparently known as tricksters) and a great base for entertainment purposes too.

So, logically speaking, it is possible if you bend the rules of what is or is not "real."

Strictly speaking though, anything that is a creature of myth is not and most was never living within the physical skin it has been depicted as, it would all be energetically/non-physical in origin.

And, most myths and legends, though twisted and exaggerated as it may seem, is or was based on a current idea or person or event at some point in time and was often regarded as being as true and real as everyone here and now.

I think such things should always be kept in mind when a person thinks of spirituality, because often people agree that there is far more than meets the eye in any experience we share, and the ways we portray that may seem convoluted at times, but there is always some shred of reality and truth rooted within any experience whether it be fabricated from the mind or experienced externally among others.