Staying In

"Seriously? Seriously?!" Sam and Dean get trapped in a medical soap with an uncanny resemblance to "Grey's Anatomy."

There’s often a certain negative stigma that comes with admitting that you watch a television show about two demon-hunting brothers called Supernatural on the CW network. You thought Buffy the Vampire Slayer had it hard? Please.

It’s a shame because Supernatural has accomplished a rare feat: It’s only gotten better and more ambitious with time. While many shows start to fizzle after their first couple of seasons or get lost in their own mythology, Supernatural has only gotten richer and more satisfying. With each season, the mythology has deepened in a way that seems completely pre-planned and non-convoluted. When last season’s major mythology backstory episode “In the Beginning” aired, I was floored. It tied in to events that happened all the way back in the pilot and, yet, it flowed like it was always meant to be.

But Supernatural is more than just mythology. It’s a show that likes to have fun and challenge itself. Like Medium, another one of my favorite shows, Supernatural likes to play with tone, format and its own existence in the pantheon of horror and television. If you need proof of its inventiveness, just check out last season’s “Monster Movie,” a black and white tribute to classic  movie monsters.

This Thursday brings yet another ambitious hour with “Changing Channels” (check out pictures from the episode here), which instantly became one of my favorite episodes of the show. Written by Jeremy Carver and directed by Charles Beeson, the episode finds Sam and Dean trapped in a series of different television shows when the Trickster returns. Like last season’s super-meta “The Monster at the End of the Book,” “Changing Channels” is a hilarious hour that also has major mythology revelations.

The episode opens with Sam and Dean in a sitcom.

“Supernatural is filmed before a live studio audience,” a voiceover says.

The show’s bloody title card has been replaced with Supernatural sitcom opening credits — two words: tandem bike — that had me laughing so hard, I was nearly crying. There’s a song (I need it as a ringtone, stat!) and stars Jensen Ackles and Jared Padalecki looking like they’re having the time of their lives while acting like the goofballs they usually are on the show’s gag reels. It’s very reminiscent of the Cordy! show opening on Angel.

The boys also find themselves starring in Dean’s guilty pleasure, “Dr. Sexy, M.D.,” alongside Dr. Ellen Piccolo, Dr. Wang and the ghost of Johnny Drake at Seattle Mercy Hospital.

“So this show has ghosts? Why?” Sam says incredulously. Thank you! If anyone should have Jeffrey Dean Morgan (who played the brothers’ now dead father) wandering around as a ghost, it’s Supernatural.

Sam and Dean also get trapped in a crime procedural full of “no talent douchebags” who wear sunglasses at night and a Japanese game show, which is painfully hilarious and surprisingly sad. That’s not even mentioning two parodies not seen in the promos that are so surprising and good, I simply can’t spoil them.

Carver, Beeson and the cast completely commit to the parodies, changing up the direction, look, sound and feel of the show to fit each parodied show. I was impressed by just how far they went, even getting a “Grey’s Anatomy” tune from Anya Marina and several other familiar music pieces. You don’t have to be a fan of Supernatural to enjoy the parodies. You just have to be a fan of television.

But “Changing Channels” is not just fanciful amusement. Whenever the Trickster (the always enjoyable Richard Speight, Jr.) comes around, there’s usually a lesson to be had and “Changing Channels” is no different. In “Tall Tales,” it was about putting arrogant pricks into their place. In “Mystery Spot,” it was about teaching Sam that Dean is his weakness. Like “Mystery Spot,” “Changing Channels” takes a serious turn. There are no happy endings and tidy bows for the Winchesters like there are in the shows they travel through, the episode reminds us. It’s a message that harkens back to “Monster Movie” (“Life is small, meager, messy. The movies are grand, simple, elegant.”) and one that the show has always embraced, never letting its characters escape their circumstances.

Supernatural airs Thursday at 9 p.m. on the CW.