If anything, its folklore prototype seems to have been the Wildman. Wildmen aren't just found in America in the shape of Bigfoot, belief in them was widespread in Europe.
The Ogre, however, seems in some degree special. In the tale of Puss in Boots,for example, the ogre had shapeshifting powers. An ogre seems to have been generally conceived as hefty, horrible, cannibalistic and, while not quite a giant, on the road to becoming one.
This has led some to trace him in origin to the Roman god Orcus. Orcus is a somewhat obscure deity in classical mythology. Sometimes he was identified with Pluto and, in the minds of the average Roman, there may not have been a clear distinction between the two. He may have been ultimately of Etruscan origin. He seems to have survived in Italian folklore as a wizard who later became a spirit.
In Ariosto's Orlando Furioso (16th Century) we are well on the way to the development of the ogre in the character of Orco, a terrible monster. Orco, though a humanoid, was extremely tall and instead of eyes he had two bones sticking out, the color of fungus; he had tusks and a snout, while he kept dribbling onto his chest. His snout was pointed downwards, so he could sniff the ground like a bloodhound.
From this image, it was but a short leap for the fairytale ogre to develop. The female of the species, the ogress, was to be featured in the works of Perrault and Countess d'Aulnoy. We shall now turn our attention to one particular ogress.
The Ogress - more scary?
Children seem particularly frightened of hag-like creatures. I suspect there is, among children, a particular repugnance to the withered features of the old, possibly because they associate them so much with traditional drawings of witches. If you want to tell a child a really scary story, throw in a hag.
The ogress was probably conceived in imagination as hag-like. However, Perrault brought one into the tale of the Sleeping Beauty. I don't refer to the evil fairy, even though she was sometimes conceived as a crone or deformed. In Tchaikovsky's ballet, she was called Carabosse, which means a hunchback. Quite apart from her, at the end of the story the Prince becomes King. His mother, the Queen Dowager, is an Ogress. By now the Prince and Princess have two children and the Ogress casts gluttonous eyes upon them. When the King (formerly the Prince) is away, she tells the Cook to cook one of the children. The Cook hides the child and serves up substitute meat. Then he is ordered to cook the second child and does likewise. Then she decides to dispose of the Sleeping Beauty herself. She prepares for this a pot of serpents into which she plans to cast her unhappy daughter-in-law and things are looking grim, until the King comes back, the Ogress falls into the pot of snakes and they all live happily ever after, except for the Ogress.
The only problem here is that this addendum to the story isn't very good from a constructional point of view. Its a sort of unnecessary appendage to the main plot. Where did it all come from?
The original story
The original story of the Sleeping Beauty is to be found in the Pentamerone (17th Century) and it's fairly shocking. The Sleeping Beauty, dormant, is found not by a Prince, but by a King. The King, finding her in this unresisting pose, rapes her. He then goes away. Not alone is he a bounder and cad, he is also has a stepmother.. Nine months later, twins are born to the Princess, whose name, by the way, is Talia. Talia is still fast asleep, but the clever infants work out where food is to be found. Thither they crawl and in due course Talia awakens.
The King, out hunting, decides to drop in on Talia (?literally) and is overjoyed to find her awake with his two children. They then form a joyful association - hmm, there's a lot of it about - but the stepmother gets wind of what is going on. When the King is away, she has the twins brought to the castle and orders the cook to cook them. He substitutes other meat - in this case goat - and the stepmother feeds it to the King. The King goes away again and the Queen brings in Talia, intending to throw her on the fire. The King returns in time, however and guess who gets thrown on the fire.
In Perrault the Ogress takes the place of the stepmother. The Ogre is not a cryptid as such, but I feel this portrayal had much to do with etching the Ogre firmly in the western mythical imagination.