There's an unwritten code among movie critics that even if you hated a movie, you don't spoil the ending in your review. If you feel you can't adequately explain why you loathe the film without also describing its finale, then at least you warn the readers that spoilers are a-comin'.

But what if a film's plot twists are so vile and offensive that you feel obligated to warn people away from the movie, "spoiler alerts" be damned? What if being evasive on the specifics would be a disservice to the readers, who might see the film and be as horrified and sickened as you were? Don't you owe it to them to do whatever you can to prevent that?

Splice has struck just such a nerve with some critics. (This post does NOT contain spoilers.) The sci-fi thriller got mostly good reviews when it opened last Friday, but the critics who don't like it REALLY don't like it. Many of their reviews freely mention some specific third-act plot points that would normally be considered out-of-bounds without a spoiler warning. In some cases, those scenes appear to be WHY the critic didn't like the film -- which means maybe it's reasonable to spell it out. Maybe you'd be a lousy critic if all you could say was, "Some very distasteful things happen in the movie, but I can't tell you what they are, but you shouldn't see it."

The issue came up last week on Movie B.S. with Bayer and Snider, the Internet-radio podcasty program thing that Jeff Bayer and I host. Jeff hated Splice. While he wasn't very keen on it for the first 75 minutes either, I think it's fair to say the last half-hour is what ruined it entirely for him. It left a bad taste in his mouth. He said he can't imagine recommending the film to anyone he knows.

Certain terrible things occur in the last act of Splice. I'm not going to tell you what they are. Suffice it to say that they are terrible. Jeff's point was that while it's possible for a movie to include depictions of these Terrible Things for purposes of shock, horror, or entertainment and still be acceptable, this movie didn't pull it off. In this case, he said, the attempt was laughable, and the Terrible Things were cheapened.

That's a reasonable reaction. The problem is, how do we review the film on the show? I think the movie's pretty good. I don't want to spoil the startling things that happen near the end. Jeff hates it -- but the simple act of saying, "This film is reprehensible because it contains [Terrible Things] and treats them laughably" would be a spoiler. The presence of [Terrible Things] is not noted in the film's poster, trailer, or advertising. Audiences aren't expecting [Terrible Things]. Which is kind of the point: It's supposed to be shocking when it happens. But that also goes to Jeff's point, which is that [Terrible Things] shouldn't be used purely for shock value.

Do you see the dilemma?

No doubt there are many moviegoers who are considering seeing Splice who would change their minds if they heard Jeff's case against it in detail. They would thank him. "We had no idea it was going to have [Terrible Things]!" they would say. "If we'd seen it, we'd have been sorry. Thank you for sparing us!" Jeff would be lauded as a folk hero, his name praised forevermore.

On the other hand, Jeff's response, while not uncommon, is not the most prevalent. Most critics have given the film positive reviews, suggesting they didn't find the Terrible Things unduly traumatic, or at least not to the extent that it became a deal-breaker. But on a third hand, just because you're in the minority doesn't mean you need to shut up. If you have an honest, legitimate negative reaction to something -- and not just its artistic merits, but its moral implications -- should you censor yourself just because your reaction is not the most common one?

I don't know if there can be any hard-and-fast rules here. What's over the line for one person may not be over the line for someone else. For that matter, something that's over the line for you in this instance might not bother you in another case, depending on the context. We go back to the Supreme Court's famous description of obscenity: It's awesome, and we should have more of it. No, sorry: I know it when I see it.

Splice didn't have this effect on me. But I can imagine the hypothetical possibility of a movie's final moments being so reprehensible to me that I would seek to "spoil" them for anyone who would listen. The people who had enjoyed the movie would probably be angry that I'd ruined it for others, though, so I'd need to be sure I was willing to stand up against what I believed were the movie's unforgivable deeds. You have to choose your battles. You pull a stunt like that very often, you become a crusader, and nobody likes you. But I think everyone's entitled to take a stand now and then.

HOWEVER: Several of the critics who dish the details on Splice seem to be doing so out of snarkiness, not moral outrage. That's when it starts to look like a regular ol' case of "I hated this movie, so I'm gonna ruin it for you," which is pure bastardry. Not all of them have that vibe, but some do. If you've seen the movie and want to see how spoiler-y some of the reviews are -- or if you just want to read the spoilers -- go to Rotten Tomatoes and bring up just the "Rotten" reviews. The ones by Amy Nicholson, Ann Hornaday, James Berardinelli, Mick LaSalle, and Rex Reed reveal more about the film's plot than they should, all without spoiler warnings. (Actually, Reed does include a spoiler warning: after he's already spoiled most of it.)

The most efficient, though, is Ed Gonzalez, at Slant, who describes the Terrible Things in no uncertain terms but gives a spoiler alert first. In most cases, that's the way to do it. Unannounced spoilers should be reserved for when you really, really want to make an issue of something. I guess we're lucky such things don't come up very often, or else reviewing movies would be a much more stressful occupation.