At the end of tonight's Girls, Adam's new girlfriend, Natalia — having just been subjected to the kind of rough, fetishistic sex that Adam prefers — pushed him off with a grimace and said, "I really didn't like that." I wonder how many viewers nodded in agreement. "On All Fours" was a relentlessly unpleasant half-hour of television, and whatever that episode was, it wasn't a comedy; by the end it was darker, nastier, and harder to watch than any TV drama I've seen this year (including the one about a zombie apocalypse).

But the episode didn't start in nightmare territory. Girls has been exceptionally self-aware this season — there's a reason, for example, that Hannah's obsessive-compulsive fixation with the number eight was introduced in this season's eighth episode — but "On All Fours" spent its first half taking the show's obsession with self-commentary to another level. Hannah's editor at Pumpt Magazine asks her to write exclusively about times when her "pudgy face was slicked with semen and sadness," as Girls itself is often accused of doing. Marnie's self-styled pop version of Kanye West's "Stronger" recalls the 2010 YouTube music video that brought Allison Williams her first moment of fame. Even the DJ at Charlie's party was playing a song that seemed to consist of someone shouting "girls, girls, girls" over and over again.

But the winking, self-referential touches of the episode's opening scenes made its genuinely disturbing ending feel all the more like a gut punch. "On All Fours" was built around a trio of horrors: Hannah's ear injury, Marnie's awkward performance, and the unpleasant sex scene between Adam and Natalia. (For now, we were spared the spectacle of a Ray/Shoshanna blowup, though I'm not optimistic about their chances next week.) Like much of Girls' second season, this episode was about self-destruction. It wasn't enough for Hannah to accidentally hurt her left ear; her O.C.D. meant she had to go back in and risk hurting her right ear too. Marnie and Charlie embraced mutual self-destruction with a misguided hookup in his office immediately after her misguided musical performance at the party. And Adam botched the beginning of a promising new relationship by drinking, and then by subjecting Natalia to his fetishes without warning or consent.

This is enormously risky material, and as always, I admire Girls' willingness to tackle issues that most shows wouldn't touch. Unlike last week's out-of-nowhere O.C.D. diagnosis, these developments even made sense. Like Hannah, we've been asked to judge for ourselves whether Adam is charming/creepy or just creepy/creepy from the moment he was introduced — but realistically, we've always known the answer.

But I wonder if Girls, like its characters, is on the verge of self-destructing. Ratings are down this season, and it was recently revealed that Lena Dunham quietly let go of a number of the show's writers before beginning season 3 — including Steve Rubinshteyn and Deborah Schoeneman, who co-wrote last week's problematic episode. The show has never felt as directionless as it feels now, and I'm not convinced that punishing loyal viewers with an episode as unpleasant as "On All Fours" — albeit a very well-executed episode — was the right move for a show that hasn't been firing on all cylinders for a few weeks. Lena Dunham may have decided that Girls is a drama, not a dramedy — or even some kind of nightmarish series about body horror, if this week's episode is any indication. But whatever this show wants to be, it needs to have a clear idea of what that means going forward. I'm hoping that next week's finale points to a brighter future for the series after this strange, muddled second season.

Unfortunately, based on what we've been seeing lately, I'm not convinced that Girls can stick the landing. After the all-fours sex scene that gives the episode its title, Adam responds to the shaken, disgusted Natalia by asking, "Is this it? Are you done with me?" I suspect many viewers found themselves asking the same question about Girls tonight — and I wouldn't blame any fans of the first season that look at this darker, stranger season and decide the answer is "yes."

Read more Girls recaps:

*Girlsrecap: 'It's Back'

* Girls recap: A disastrous trip outside Brooklyn

* Girls recap: A night out with the boys

* Girlsrecap: 'One Man's Trash'

* Girlsrecap: 'It's a Shame About Ray'

* Girls recap: Hannah the antihero

* Girls recap: 'I Get Ideas'

* HBO's Girls season 2 premiere: Almost getting it kind of together