Well, I’d say that a “mythical” creature with so many different names in so many cultures on several different continents going back centuries actually isn’t mythical at all. No idea what they actually are. But, they do appear to be a very large, hairy species of hominid, generally reclusive and elusive, that on occasion display a strong dislike of being encroached upon. In known species this sort of behavior is usually tied to males during mating season or females with young.
Neanderthals are supposed to have died out about 40,000 years ago. It is sometimes suggested that very small relict populations in particularly remote/cold/mountainous areas might have persisted much later, giving rise to the very ancient folklore found in so many places about giants, trolls, ogres, etc. up in the mountain caves. That may be nothing more than romantic nonsense -- there seems to be a spectacular lack of evidence other than old stories with no more foundation than today's anecdotal sightings -- but: the wooly mammoths lingered on until about 4,000 years ago, finally dying out as the Egyptians were well into the Age of the Pyramids.