"Piranha 3D" is a movie that wants to have its cheesecake and eat it too
. I mean this more or less literally. The entertainment formula behind this short and nasty movie devised according to someone's idea of what teenage boys with the guile, the facial hair or the "guardian" to gain admission to an R-rated movie are likely to enjoy is sloppy and simple. Young women dance around in, and frequently shed, their bikinis, and are then devoured by swarms of predatory fish.