peryton
This isn't quite a real word, but since that has never stopped me before, I looked around to see what I could find about its usage. A peryton is a mythical beast, composed of the body of a stag and the wings of a bird. They're actually quite majestic in a lot of the artwork depicting them. Also fairly irrelevant, but I think it's interesting it is an anagram for entropy.
The term was coined in a very interesting book, the title of which is A Book of Imaginary Beings in English, by Jorge Luis Borges and translated by Norman Thomas di Giovanni. Its original Spanish title from the first 1957 printing is Manual de zoología fantástica. The book received a few updates over the next couple of decades before landing on the final Spanish title, El libro de los seres imaginarios, in 1969.
There is a fairly long, but very interesting passage on them in the book. Their most pertinent details are originating from Atlantis, having the shadow of a man until they manage to kill a human, at which point their shadow is restored to their own figure, and being very bloodthirsty, violent creatures.
I found fleeting mentions of similar beasts before Borges' book, but none especially substantial, suggesting there was either predecessor to his creation or some inspiration for it. Either way, this particular version of the concept came from Borges, who originally penned it as the Spanish peritio.
However, this word has gone on to accumulate more meaning, and after a publication by S. Burke Spolaor et al., the term was adopted into astronomy as meaning "a terrestrially originating burst of radio waves." (As someone who is very not an astronomer, I can't explain what this means, but apparently you can produce them by opening a microwave door prematurely).