The Yedua is a plant-creature recorded in the Talmud [edit: it isn't, it's recorded in later appended discussion of the Talmud. Apologies]. Tethered to the ground by a vine, they grow into human-like shapes. Any creature straying too close to a Yedua is killed and devoured. Only by severing the plant-man from its roots can the Yedua be defeated.
The Yedua (variously also spelled Yadu’a, Jeduah, and Fedua) are part of a strange subcategory of plant-lore in which the line between flora and fauna has become blurred. The humanoid, screaming Mandragora root – the Mandrake – has already been discussed, but before we get on to the Yedua, there are a couple of other notable examples.
The Barnacle Goose (a real species of actual goose) was, for a long time, thought to grow on trees (or on wood, at least).
There are likewise here many birds called barnacles,(barnacle geese) which nature produces in a wonderful manner, out of her ordinary course. They resemble the marsh-geese, but are smaller. Being at first, gummy excrescenses from pine-beams floating on the waters, and then enclosed in shells to secure their free growth, they hang by their beaks, like seaweeds attached to the timber. Being in progress of time well covered with feathers, they either fall into the water or take their flight in the free air.
The above words were written by the archdeacon of Brecon, Gerald of Wales, in his book Topographia Hiberniae, around 1188 AD. It should be noted that Gooseneck Barnacles are also real things, which do bear some co-incidental resemblance to Barnacle Geese, but lack of knowledge of the migration of birds seems to have been the main factor at play here. That and the fact that if these geese weren’t strictly geese, they could technically be eaten freely on days when religious observances called for abstinence from meat.
The Vegetable Lamb is another strange example. Widely believed now to have come from the first reports of the cotton plant, with its wool-like yield, the Vegetable Lamb seems to have undergone a significant number of evolutions in the retelling. Some stories tell of a large gourd, inside of which, when ripe, could be found a lamb-like creature. Others tell of a living, moving, grazing lamb-like fruit, tethered to the plant from which it grew by means of an umbilical vine. It is this latter version of the Vegetable Lamb which bears a striking resemblance to the Yedua.
In the Mishna Kilaim (vin, 5), a portion of the Talmud, we meet the passage, "Creatures called adne sadeh ('lords of the field') are regarded as beasts." Rabbi Simeon, who died about 1235, comments on this statement as follows: " It is asserted in the Jerusalem Talmud that this creature is the 'man of the mountain.' It draws its food out of the soil by means of the umbilical cord: if its navel be cut, it cannot live. Rabbi Meir, the son of Kallonymos of Speyer, has added these remarks:
'There is an animal styled Yedua? with the bones of which witchcraft is practised. It issues from the earth like the stem of a plant, just as a gourd. In all respects, the yedua has human form in face, body, hands, and feet. No creature can approach within the tether of the stem, for it seizes and kills all. As far as the stem (or umbilical cord) stretches, it devours the herbage all around. Whoever is intent on capturing this animal must not approach it, but tear at the cord until it is ruptured, whereupon the animal soon dies.'"
This quotation is taken from a 1915 article taken from The Journal of American Folklore, written by Berthold Laufer. Why would anyone want to kill the Yedua? Well, apart from the fact that it seemed to want to murder anyone who came too close to it (the same could be said for many wild animals though, to be honest), the bones of the creatures were thought to be useful in magic. If held in the mouth of a sorcerer, the bones (exactly what form these plant/animal bones would take is not recorded) were supposed to grant them the ability to foretell the future.