Accidental travel is a speculative fiction plot device which an ordinary person or a group of people accidentally find themselves outside of their normal place or time, often for no apparent reason, a particular type of the "fish-out-of-water" plot. In Russian fandom, the trope is known under the term popadantsy, plural form for popadanets, female: popadanka, a person who accidentally finds himself elsewhere/elsewhen. The Russian term bears ironical flavor, because popadantsy has become a widespread cliche in Russian pulp science fiction. Russian critic Boris Nevsky traces this plot device to at least Gulliver's Travels (18th century). In Japanese fiction, the genre of accidental transport into a parallel universe or fantasy world is known as isekai.