Some mythological creatures are more famous than others, but a few are so famous that their entire species has been named after them in the popular consciousness, in a kind of mythological malapropism -- or, alternatively, a singular creature proposed as a unique aberration is adopted by other stories as if it were a species. The ancient phrase for this trope is sui generis, roughly "a thing that defines its own category". For instance, someone encountering a creature for the first time may Call a Pegasus a Hippogriff. Trope name is a reversal of "one of a kind".