Supernatural is supported by its marked unreality: for Sam and Dean Winchester, hunting demons has become their normal lifestyle. To be sure, it has not come easily: aside from the exhaustive job they’ve taken on, they’ve also suffered a personal toll through losing their parents and being turned against one another time and again. (I’m trying to keep this mostly spoiler-free for those who want to follow the entire series’ arc, and because those developments are not the backbone of this essay.)
And yet, the series never loses its comedic touch or flair for parody, utilizing this self-referential style as the best tool with which to simultaneously force Sam and Dean to examine their odd lifestyle, as well as to acknowledge Supernatural’s vast fanbase. Three episodes in particular (from the first, third, and fifth seasons) attack the boys’ lifestyle through interactive pop-culture mainstays: an urban legends website; reality television; and a fan convention. In each instance, the Winchester brothers find themselves facing at least archetypes of themselves, if not actually themselves, prompting them to reevaluate the point of their ongoing struggle against evil.
Aristotle’s Poetics concerns itself with mimesis, or the mode of imitation that distinguishes poetry. Unlike in Aristotle’s examination of poetry (which contained varying forms that he nonetheless counted under the same umbrella term), my study of Supernatural includes three different media, as mentioned above: website, reality series, and fan convention. The objects (“men in action”) are in each case Sam and Dean; and finally, the manner, or narration, takes its form through people, “living and moving before us”. 
At first, the bonds between Sam and Dean and their imitators are shadowy at best: In 1×17 “Hell House”, they run into Ed Zeddmore and Harry Spengler in the eponymous haunted house. The latter are nerds laughably calling themselves “paranormal investigators”. Sam and Dean are initially too surprised to do anything but go along with the two, who puff up in self-righteousness about their tools and strategies in finding ghosts. In contrast to Sam and Dean’s fairly sparse gear (flashlights, salt, lighter, and guns), Zeddmore and Spengler are decked out in night-vision goggles and something approximating Ghostbusters‘ Proton Pack. (Fun fact: The characters’ surnames are taken from two Ghostbuster members!)
It turns out that there is a demon haunting the house — a tulpa, which comes to life through people’s imaginings — but the only reason it’s stayed alive is due to the Hell Hound’s Lair’s readership and their fervent beliefs in the demon accounts. It’s an apt metaphor for the viewers who keep a show, especially a quirky paranormal one like Supernatural, afloat. By the end of the episode, the boys burn down the house inhabited by the ghost, and Sam suffers a slight crisis:
“It kinda makes you wonder… of all the things we’ve hunted, how many existed just ’cause people believed in ’em?”
And yet, that anxiety is short-lived, as Sam and Dean accept (without the need to explicitly say so) that the demons they hunt are “real”. And while Zeddmore and Spengler in some ways imitate Sam and Dean, what we really see through them is the boys coming together against “themselves”: the episode’s subplot involved the Winchesters in a prank war, which concludes when each of them pulls a prank on the Hell Hound’s creators instead.