Otherkin
From RationalWiki
Otherkin is a term referring to a bunch of self-marginalising, self-absorbed weirdos vibrant alternative community who believe that they are, at heart, aliens/star people/elves/unicorns/what-have-you who are currently embodied in human bodies. It should be noted that while many religions have somewhat dubious beginnings and basis for their being, those who would refer to themselves as otherkin tend to believe they are spiritually beings that have verifiably never actually existed.
Therians are a similar subculture, who identify with specific animals rather than mythical creatures. Of course, because these are real animals, that validates their perfectly normal beliefs. Yeah right.
Both of these terms are very recent, and have been popularised by the internet. In 1996 the term "therianthropy" was just coming into use because some felt lycanthropy was wolf-centric and wanted something to include other species. "Therian" is a shortened version of "therianthropy" but it didn't come into use until several years later (sometime after 2000). Nobody is quite sure where "otherkin" originated, except that it seems to have been yet another attempt at a more inclusive term, one which also included people who believed that they were actually vampires and Vulcans and dragons and whatnot.
Some otherkin suffer from psychological trauma due to feeling trapped in "the wrong kind of body". Reportedly, some even experience psychosomatic symptoms of sensations in non-existent wings, tails, and other limbs.
[edit] FYIAD
FYIAD is an otherkin related term that originated when a member of the community was arguing with mentally-balanced people in regards to the authenticity of his beliefs. Like all immature losers on the net, he quickly lost his temper and proceeded to pwn(haha no) everyone by typing "FUCK YOU I'M A DRAGON". What began as a logical debating tool has since been thrown around whenever otherkin show up and their presence is not wanted, which as a rule, is all the time.

