**_Pot-soaked teens in SoCal harassed by a possessed hand_** A town is plagued by a series of killings as a group of unambitious high schoolers (Devon Sawa, Seth Green and Elden Henson) trace the problem to the uncontrollable appendage of one of their own. “Idle Hands” (1999) is a manic horror comedy with macabre humor and lots o’ gore, influenced by bits from flicks like “Evil Dead 2,” “Re-Animator” and “An American Werewolf in London.” It’s often legitimately funny because it takes situations or lines and goes one step further for an over-the-top effect, similar to “There's Something About…