Bachelor party goes so wrong

Based on one of the best segments from the hit horror anthology “V/H/S,” the slick thriller “SiREN” loses the found-footage format of the original but keeps the concept of randy bros getting in over their heads. Director Gregg Bishop re-imagines David Bruckner’s grubby “Amateur Night” into something granderscaled, if not as viscerally terrifying.

“Amateur Night” told the story of crude dudes coercing drunken women into their motel room to make hiddencamera porn, but “SiREN” is set at a bachelor party, where the sweet-natured groom Jonah (played by Chase Williamson) gets pushed by his debauched brother Mac (Michael Aaron Milligan) into visiting a backwoods brothel run by supernatural pimp Mr. Nyx (Justin Welborn).

“SiREN” divides up its action, with about half covering Mr. Nyx’s demonic dealings at his gothic mansion. The rest follows what’s going on outside with Jonah, who makes the mistake of freeing a prostitute named Lily (Hannah Fierman, reprising her “Amateur Night” role) who turns out to be a literal harpy, complete with bewitching song, scaly wings, and razor-sharp teeth and tail.

The expanded locations and talented cast give “SiREN” a satisfying oomph, although in the process of telling a fuller story Bishop diffuses the scares while losing some of the original’s scathing commentary on macho entitlement.

Still, for the most part this is a clever and confident expansion of a terrific short. It stings less but packs plenty of poison. “SiREN.” No rating. Running time: 1 hour, 22 minutes. Playing: Arena Cinelounge, Hollywood.