“Megalodon Rising” (*1/2 out of four) was a thirdhand “Jaws” wannabe about yet another gigantic killer shark who swims into military waters and a rogue navy crew (Tom Sizemore, Wynter Eddins, O’Shay Neal, and others) who attempt to exterminate it once and for all. The shark scenes and effects are vivid but they’re few and far between; the rest is utterly by-the-numbers. Maybe it’s time by now they put the killer shark genre to rest for a while before it’s entertainment value becomes utterly extinct.