One has to wonder what the late Jim Henson would think of his son Brian’s decision to take the family business into hard-R territory via a division called Henson Alternative. But whether he would have approved of the attempt or not, his boy’s initial effort along those lines is definitely a pseudo-Muppet movie that, while being way too raunchy for kids, has little to offer to adults, either. “The Happytime Murders” is a debacle of “Howard the Duck” proportions.

The premise is curiously reminiscent of Netflix’s recent bomb “Bright.” Los Angeles is once again a place divided in population terms, except that the downtrodden minority this time around consists of puppets rather than orcs. As in the earlier movie, however, one of the critters did successfully break the barrier against puppets serving on the LAPD—Phil Phillips (voiced and operated by Bill Barretta).

Phil’s stint on the force ended in ignominy, though, when he failed to rescue his human partner Connie Edwards (Melissa McCarthy), who was being held hostage by a puppet criminal. Phil’s shot went wild, killing a hapless puppet walking with his daughter on the street. Edwards was wounded too, and in a panic Phil took her to a hospital exclusive to his own species, where she was fitted with a puppet liver. That explains why she has a craving for sugar, and is so contemptuous of Phil, who was deemed unwilling to shoot other of his kind and removed from the department.

Now Phil is a private eye in cynical Sam Spade mode, and he takes on the case of Sandra White (Dorien Davies), an extra-sultry femme fatale who’s being blackmailed. The investigation takes him to a puppet sex shop, where a masked intruder kills a bunch of workers and customers, including Mr. Bumblypants (Kevin Clash), who was once a regular on “The Happytime Gang,” a popular TV show that a bevy of the furry critters shared with a single human, Jenny (Elizabeth Banks), who was also once Phil’s girlfriend.

When Connie arrives to take charge of the crime scene, she brusquely dismisses him until another killing occurs—of Phil’s own brother Larry (Victor Yerrid), who played a cop on “Happytime.” Accepting Phil’s hypothesis that the culprit is targeting cast members, LAPD Lieutenant Banning (Leslie David Baker), a crusty old school cop, orders Connie and Phil to work together on the case. As they do so and corpses (or more accurately bits of fabric) pile up, of course, the animosity between them two melts away. Ultimately the identity of the villain and the motive behind the killings are revealed.

On the one hand “The Happytime Murders” is a spoof of pulp-based movies like “The Maltese Falcon,” much as earlier Muppet features from the Henson stable took on took on other genres or just remade classics like “A Christmas Carol” or “Treasure Island.” While all of them were family-oriented, however, this one is most defiantly not. It revels in vulgarity, whether it be in the non-stop dropping of F-bombs, the casual nastiness as puppet characters are beaten, torn apart or kicked around, or—most significantly—scenes that would, if played by human actors, be the stuff of X-rate porn. The most extreme example is a long sequence in which Phil and Sandra engage in an impromptu bout of steamy sex in his office as Banning, an officious FBI agent (Joel McHale) and Phil’s secretary Bubbles (Maya Rudolph) embarrassedly listen to the action—a lot of white Silly String explodes in all directions as Phil reaches the point of no control. But that’s merely the tip of the iceberg, as it were.

One’s ability to enjoy this will depend on whether you find grossness for the sake of grossness any more tolerable when it’s enacted by Muppets rather than human beings. If you’re a big fan of Apatow-style comic raunchiness and its inferior imitators, of course, this might be to your taste (or lack thereof); but Seth MacFarlane’s “Ted” movies, among others, played much the same tune as this one on a smaller scale, and Henson’s doesn’t mark any improvement on them.

Certainly the movie has little else going for it: the plot is as dopey as anything on the old Muppet Show, and the dialogue drips with the sort of goofy malapropism and parody the series specialized in, but it all seems drearily uninspired this time around. McCarthy offers another of her frantic, frenzied, deeply unfunny turns, and Banks is pretty much wasted, although Rudolph manages to get a few laughs as Phil’s absurdly loyal secretary.

There is, however, a lot of technical dexterity behind the work of animating the puppets and ensuring that the interaction between them and the human actors is smooth and seamless; footage during the prolonged final credits testifies to the efforts of the puppeteers and crew in choreographing things. Praise is certainly due the Henson factory and cinematographer Mitchell Amundsen for putting it all together so skillfully.

It’s a pity their talents weren’t in the service of better material.