In Search of Lost Time Travelers
As James Gleick demonstrates in Time Travel: A History (2016), fictional characters have been traveling to the future and the past for centuries, but time travel as a distinct notion is surprisingly new. It was H.G. Wells who shifted the concept from pure fantasy to the realm that would eventually be known as science fiction when he published his novel The Time Machine in 1895. The very fact that the book's title now seems so generic underscores just how influential Wells actually was: apparently, no one before him had though to put "time" and "machine" together.
The result was not only the eventual proliferation of time travel stories, but a particular framework rooted in science and logic: time travel can create paradoxes, and therefore becomes an irresistible logical puzzle. Ask the average person what their associations are with science fiction, and they will probably mention robots, spaceships, and time machines. Within the science fictional framework, time travel stories are an ideal testing ground for ideas about determinism and free will, as well as about the importance of the individual person or event and the overall make-up of the cosmos. And, of course, time travel provides endless possibility for adventure.
With the exception of adventure, however, most of these concerns are irrelevant to the Time Crasher phenomenon. Not only do these stories rarely even bother with mechanical or pseudo-scientific contrivances, they don't tend to care at all about the method of travel. As for the possibility of paradox, their concern is selective and sporadic at best. They lack a fundamental feature of science fictional time travel stories: an implicit or explicit theory of time. Despite the enduring centrality of H.G. Wells to the Russian understanding of fantastika, most Time Crasher stories are written as if over a century's worth of science fictional time travel tales had never been written. We should recall that the Russian equivalent of "science fiction" is "nauchnaia fantastika"--"scientific fantasy." The Time Crasher genre jettisons the "scientific" in favor of the "fantasy."
A time machine, of course
Instead, the Time Crashers follow in the tradition made famous by Mark Twain in his 1889 novel A Connecticut Yankee in King Arthur's Court. The titular Yankee ends up in Arthurian England after a blow to the head knocks him unconscious. When he wakes up, he is in a different time. One might ask: exactly how does this work? The correct answer is crucial to appreciating the story: nobody cares.
Readers of Time Crasher stories have no particular reason to believe that a head injury, a mysterious fog, or lying on one's deathbed are feasible means of time travel. Rather, they make different demands of the text. In this, Time Crasher stories differ from other hardcore F&SF genre entertainments, whose devoted fans often derive satisfaction from expanding and interrogating a particular text's or franchise's lore. This holds true for fantasy as well as for science fiction, as even a cursory familiarity with Harry Potter fandom demonstrates. These fans find as much pleasure in the mechanics of the imaginary tale as they do in the tale itself. All Time Crasher readers need is some vague handwaving to get all the players where they are supposed to be.
Generally, in both fantasy and science fiction time travel is expected to be replicable, but Time Crashers primarily travel by means that are idiosyncratic and personal. A pre-teen science fiction reader might try to build a time machine, but they are unlikely to induce a head injury in order to kill baby Hitler. This underscores the frequent status of the hero as an authorial stand-in: it is the authorial sensibility (and ideological agenda) that is making the trip to another time.