Season seven's threat is in full effect on Supernatural in the black ink from Purgatory that is Leviathan. I love the opening salvo of this Wikipedia entry about the use of the word "Leviathan" in the Christian and Hebrew biblical contexts:
In Demonology, Leviathan is one of the seven princes of Hell and its gatekeeper (see Hellmouth). The word has become synonymous with any large sea monster or creature. In classical literature (such as the novel Moby Dick) it refers to great whales, and in Modern Hebrew, it means simply "whale.
Which isn't to say Supernatural went the giant sea monster route with their depiction of the body-hopping entity. But in a nice nod to the mythology, it does get its start via the water, deployed via the exploded carcass of Castiel who appears to no longer be with us. Which was a pretty startling development for the show. Usually the arc for this kind of thing for most shows would entail a a few episodes at least of the hero-turned-villain struggling with the monster inside. Instead, Supernatural seems determined to jump right into the story, presenting all the new obstacles for Sam and Dean right up front.
With now, we don't know very much about Leviathan that makes them "must watch" villains the way Lucifer, Crowley, Lilith, and Raphael have been in the past. In fact, with the exception of a seeming lack of vulnerability, their body-hopping and gratuitous evil seems to be borrowed from the typical demon of the week schtick. Oh, and they're hungry: the four hosts we encounter this episode chow down on some human fleshy bits and by the end of "Hello Cruel World" they've found a pretty clever feeding ground. Only one episode into their official introduction, we only know a little about Leviathan, the thing that escaped from Purgatory in Castiel: it's not one entity, it can swap bodies, it's nearly impossible to kill, and it's following the lead of some player in the shadows who apparently wants to see Sam and Dean taken down.
Speaking of those two (and storylines getting pushed forward with the quickness), instead of allowing that side plot of Sam's hallucinations about Lucifer plague the rest of the season, the show's writers chose instead to have a resolution--possibly temporary--in this episode. I like the sentiment behind how Dean convinces Sam that he's no longer trapped in the cage with Lucifer--essentially, drawing a line between the kind of pain Sam would feel there versus the kind of everyday, mundane pain on Earth--but the execution felt a little flat. It's essentially two dudes talking while one squeezes the other's hand. It definitely got the beat across but just felt a little limp.
Still, I'm really digging the economy with which these season's moving forward and I'm looking forward to seeing how Leviathan is realized as the villain for the rest of the run.
Next week: Jensen Ackles directs!
Supernatural airs Fridays at 9 on the CW.