AHHH!: Put this franchise out of its misery.

What a fitting subtitle for Fox’s latest offense to fans of not one but two venerable sci-fi properties. Paul W.S. Anderson nearly killed both franchises with his first limp stab at pitting the parasitic “xenomorphs” of the once-great Alien series against a dreadlocked, vagina-dentata-mouthed refugee from the once-good Predator films. Now along comes this continuation that serves no purpose other than to put them out of their misery.

Colin and Greg Strause, a pair of special-effects veterans, deliver this dirge. In the three years since Anderson’s relatively bloodless PG-13-rated misfire, gore has made an R-rated comeback, driven by the rise of “torture porn.” Problem is, the only audience likely to overlook the complete lack of relatable characters, internal logic, or (most damningly) suspense in this mess is too young to purchase a ticket.

What’s left is an exercise in genre futility. A hybrid “Pred-alien” crash-lands in Gunnison, Colorado, killing pretty much everyone save the expectant mothers in the town hospital’s pregnancy ward, who are used to incubate what I can only assume are “Pred-ali-umans.” Meanwhile, another Predator shows up to clean up the mess before the inevitable, confusingly staged showdown. The film’s one-dimensional heroes — Iraq war veteran Kelly (Reiko Aylesworth), a gun-toting mom modeled after Sigourney Weaver’s Ripley, and ex-con Dallas (Steven Pasquale, a name familiar to fans of Ridley Scott’s Alien) — underline the desperation of Shane Salerno’s script. 86 minutes | Boston Common + Fenway + Fresh Pond + Chestnut Hill + Suburbs