PIRANHA 3D "OWWWWWW, MY PENIS!"

COPIOUS AMOUNTS OF GORE. Extensive full-frontal nudity. Character actors hamming it up in silly roles. These three ingredients are what summer movies are all about, and director Alexandre Aja mixes them deftly in Piranha 3D, an improbably fun reimagining of Joe Dante's 1978 Jaws rip-off.

Aja proved through High Tension and his underrated remake of The Hills Have Eyes how artfully he can amplify standard horror clichés into freshness. Piranha channels the cheeseball charm of yesteryear's teen disaster movies, and then takes joy in undercutting it as its silly death scenes get uglier and uglier. You laugh when a girl gets her hair caught in a stopped boat propeller, for instance, but then Aja forces you to watch her scalp removed in sadistic detail.

What's the story, you ask? Stop me if this sounds familiar: an earthquake opens a subterranean lake filled with ancient, killer fish. The lake is in a town that relies on spring break tourism for money. Everyone's getting naked, and everyone is in danger.

On second thought, don't stop me; it doesn't matter how tired the premise is. Piranha is aimed at every gorehound who affectionately remembers the corny elements of '80s horror films. It's the type of movie where naked hang gliders get their legs devoured, where someone pukes into the camera, and where Jerry O'Connell—who's basically playing Girls Gone Wild creator Joe Francis—has his penis ripped off, eaten, and then belched into the audience (in lovingly rendered 3D). It's the type of movie where cops say, "I'm too old for this" and warn spring-break revelers not to go in the water only to be rebuked by some slammin' party jams after someone shouts, "Hit it, DJ Chocolate Thunder!" It's the type of movie where Richard Dreyfuss gets sucked into a whirlpool and Christopher Lloyd rants about fish reproductive organs. It's the perfect summer movie.