A Shapeshifter - also called a Shifter - is a metamorphic monster that can take any shape it desires.
A shapeshifter can assume the physical and psychological signature of virtually any life form whose genetic material it has consumed. They are distinct from Skinwalkers as the latter is capable of shifting into any animal whilst a Shapeshifter can assume a human form.
Shifters would gain these abilities either through divine intervention, demonic manipulation, sorcery, spells or having inherited the ability. Regardless of how they obtained their abilities, they are extremely dangerous supernatural beings as they could very easily infiltrate society undetected and cause great damage.
Unlike the usual depiction of shifters in folklore, they would mainly assume the form of a human. Shifters are driven by three simple instincts; consume, change, breed. Shifters "feed" on the memories and genetic information of other creatures; killing them and absorbing their genes through their leathery tendrils which seem to emerge from the tips of their fingers. With this, they acquire both their genetic memory, visage, voices, and even their clothing. Young shifters require the use of one's blood to ingest in order to transform, and the more blood they drink the more they have access to the form.
While in human form, shifters are indiscernible. The only way to reveal a shifter is their eyes; their irises reflect light by reflexively blinking a vertical set of eyelid membranes similar to reptiles. This trait is also seen on camera, as all shifters appear with glowing eyes. By virtue of their versatile genetic and molecular structures, shifters are highly resilient; capable of regrowing limbs, provided they have enough biological material to consume to fuel their healing process. They cannot, however, survive beheading or being completely immolated. Shifters can even evade capture by changing their biological matter through the absorption of several drops of blood from an injured human.
Shifters may also augment their strength and durability - at the expense of their speed and agility - by channeling biomass into their muscles to harden their skin and enhance their musclemass; doubling their already-inhuman strength and enabling them to bash aside road vehicles. Upon reverting to their default states or switching to another disguise, a shifter's disguise melts into a gray viscous liquid.
Myths and Legends
Popular shapeshifting creatures in folklore are werewolves and vampires (mostly of European, Canadian, and Native American/early American origin), the huli jing of East Asia (including the Japanese kitsune and Korean kumiho), and the gods, goddesses, and demons of numerous mythologies, such as the Norse Loki or the Greek Proteus. Shapeshifting to the form of a wolf is specifically known as lycanthropy, and such creatures who undergo such change are called lycanthropes. Therianthropy is the more general term for human-animal shifts, but it is rarely used in that capacity. It was also common for deities to transform mortals into animals and plants.
Other terms for shapeshifters include metamorph, the Navajo skin-walker, mimic, and therianthrope. The prefix "were-," coming from the Old English word for "man" (masculine rather than generic), is also used to designate shapeshifters; despite its root, it is used to indicate female shapeshifters as well. While the popular idea of a shapeshifter is of a human being who turns into something else, there are numerous stories about animals that can transform themselves as well.