Piranha 3D tips its cap to Jaws with an opening appearance by Richard Dreyfuss, yet the true ancestors of Alexandre Aja's latest are less Steven Spielberg's classic (and Joe Dante and Roger Corman's more politically inclined 1978 original Piranha) than '80s-era slasher films. Unapologetically giddy about its gratuitous crassness, Aja's B movie operates by constantly winking at its audience, and while such self-consciousness diffuses any serious sense of terror, it also amplifies the rollicking comedy of its over-the-top insanity.
The story itself is barebones stuff: In a lakeside town during spring break, thousands of prehistoric flesh-eating piranhas are freed from their subterranean home by a tectonic rupture after Dreyfuss drops a beer bottle in the water. Drinking is thus the cause of the ensuing carnage, though Aja—hewing to well-worn genre conventions—makes sure that it's promiscuity that must be viciously punished. Given that his film only has boobies and blood on the brain, this means the saga occupies itself during a first-half buildup to carnage by delivering more in-your-face T&A than any mainstream release in memory, its abundance of jiggling female parts (most of them the property of supermodel Kelly Brook or assorted porn stars and models) culminating in a slow-motion underwater lesbian ballet between Brook and Riley Steele that's destined to be the most popular clip ever on Mr. Skin.
Pete Goldfinger and Josh Stolberg's balls-to-the-wall script splits time between the heroism of local sheriff Julie (Elisabeth Shue) and seismologist Novak (Adam Scott), and the adventures of Julie's son Jake (Steven R. McQueen) aboard a boat with Joe Francis-style misogynistic pornographer Derrick (a hilariously vulgar Jerry O'Connell). Aja's more-is-better modus operandi, however, doesn't extend to the plot, which is merely an excuse to indulge in both copious nudity and, once the fish reach the partying masses, outrageous nastiness. During this massacre, kids are put in peril and the horniest suffer the greatest, be it a parasailing topless woman whose legs are chomped off, a wet t-shirt contest organizer who loses his head (Eli Roth), a beauty whose torso is cut in half by a stray electrical cord (which, naturally, first knocks off her bikini top), or a male victim whose severed member is both eaten and regurgitated by the piranha.
In those and other crazy scenes (including some overboard vomiting), Aja's gimmicky use of 3D is self-aware, but the technology turns his imagery flat and, in underwater scenes, horridly murky. Regardless of these special-effects deficiencies, though, the proceedings' obscene gore is, like its softcore jokiness, so extreme and campy—epitomized by a hair-caught-in-propeller scalping—that the trashy, merciless Piranha 3D proves a worthy heir to its brazen exploitation-cinema forefathers.