A lamia is a being long thought to be mythical. They have lived on the islands found in the Aegan, Ionian, Adriatic, and Baelaric seas for millennia. A few were trapped during the second war and brought north to Britain. Voldemort thought he could use them to devour the children of his enemies and gain insight into the opposition's plans by utilising their powers of prophecies. They proved difficult to control and the climate change made most of the lamiai severely ill. The creatures were abandoned to die, which the majority did. One survived and only because she managed to live long enough to shed her snake skin.
Lamiai vastly prefer caves and other damp places for dwelling. Extremes of temperature in either direction are avoided as are any locations which are solely wet or solely dry. Lamiai require both heat and water for their survival, particularly when in their half-snake form. Usually their homes are only accessible via water. The term "lair" is often aptly applied to their dwellings.
A lamia functions on a four month schedule. Every four months she will shed her skin from the stomach down. When she sheds a snake skin a human body is found underneath. When she shedding comes while in a completely human outer form the process is identical, though what she slithers out of is legs that are replaced by a tail. Shedding for a lamia is an identical process to that of a normal snake. Before a moult, the lamia stops eating and often hides or moves to a safe place. Just before shedding, the skin becomes dull and dry looking and the eyes become cloudy or blue-coloured. The inner surface of the old outer skin liquefies. This causes the old outer skin to separate from the new inner skin. After a few days, the eyes clear and the lamia crawls or slithers out of its old skin. The old skin breaks from the skin at mid-stomach and the lamia wriggles out, usually aided by rubbing against rough surfaces. In many cases the cast skin peels backward over the body from waist to tail or toe, in one piece like an old sock. A lamia will always emerge from a moulting with the opposite bottom from that which she shed. Every four months like clockwork she will alternate between a serpent body, or a female one.
Outwardly, from the waist up the lamia always resembles a woman. However, the lamia does have both a Jacobson's organ and a forked tongue. Her tongue allows the lamia to smell just as an ordinary snake would, though her sense of smell is more sensitive. The lamia's tongue serves all the same purposes as that of a regular snake and is likewise constantly in motion. When she has the lower body of a snake the lamia gains the advantage of being very sensitive to vibration. The part of her body in contact with the ground is sensitive enough that she can feel vibrational changes in the ground and air which helps her to sense the approach of creatures and beings alike.
When in human form a lamia tend to be between five-foot-seven and six-foot one. When in her half-snake form a lamia is usually between nine and eleven feet from head to tail. A lamia stands up on her tail at about the same height she would be if she were in her fully human form with the extra feet of tail slithering along the ground to move her along. When she needs to move rapidly a lamia will lay down completely, raising her female upper body off the ground while she otherwise propels herself over the ground in the same manner as a serpent.
Lamiai are unable to close their eyes. They do possess eyelids, but they are completely immobile. The only relief their eyes get is when a lamia takes them out. She can still see through her eyes, however, though they are not in their sockets. In order to rest them the lamia will place them somewhere dark, and usually either moist or submerged in water. While her eyes are out the lamia depends on vibration sensitivity and her sense of smell to move around. Eyes are usually removed during times of rest and more often during the period of having a partially serpentine body rather than a human one.
Strictly carnivorous creatures, the lamiai eat primarily children. They have been known to feed on the children of other humanoid species as well, but humans are easier to find and taste better so they are the heavy preference for nearly all lamiai. They can survive on other species, such as birds, bovines, or other mammals or reptiles, but it is extraordinarily rare to find a lamia which subsists on this sort of diet when it is not absolutely necessary. Lamiai only have four fangs, two from the top gums and two from the bottom. Their fangs are hollow and when a lamia bites down into something or someone a venom is injected into the punctures through the fangs. The venom of a lamia contains compounds which will paralyse the victim as well as compounds which will begin circulating through the system to break down tissues and eventually liquefy the interior of the body completely.
In order to consume their prey lamiai dislocate their jaw and the skin around their face and neck stretches so that they may swallow their prey whole, digesting just as a snake would. Lamiai only eat where they will not be disturbed as their bodies need the time to digest, stretching out to accommodate the meal while it is broken down and consumed. If potential danger approaches during digestion the lamia will regurgitate and abandon the meal in favour of fleeing. Digestion is incredibly effective, only hair and nails are indigestible and excreted with the lamia's waste. Rest is necessary for at least a half hour after digestion is completed before energy exertion is possible. Two hours rest is ideal.
During the four month periods of being in a completely human form a lamia will not consume a child taller than she is long from the top of her throat to the bottom of her pelvis, though her torso will stretch up to a foot longer for more comfortable accommodation. Larger prey can be ingested however many lamiai find it uncomfortable to lay with half a child still protruding from their mouth and will avoid doing so. When she has a half-snake body the lamia is significantly longer and will indulge in children up to five and a half feet tall.
Lamiai possess the gift of prophecy. They are incapable of controlling their prophecies. They tend to occur on a near regular schedule of once every four to six months. The content and nature of these prophecies is unpredictable. Sometimes clear images and audio occur, like watching a scene play out in front of them, other times all the lamia receives is a word, a feeling or a fuzzy image. Older lamiai tend to have more detailed prophecies. It is impossible to steer their prophecies in any direction, though many have tried in the past. Some lamiai were once captured and experimented on to elicit a higher rate of prophesying but the only result was that the lamiai had their systems poisoned and they all died in a great deal of pain.
Stunning spells as well as other spells and potions to render one unconscious have absolutely no effect against a lamia. There is a natural immunity to most poisons as well as spells meant to move the beings, including levitation. Lamiai, however, are particularly susceptible to anything which deals with extreme hot or cold. Ice and fire are particularly effective in killing the beings while rings around the beings of either will keep them contained and subdued.