When a couple’s regular babysitter is suddenly (and, unbeknownst to them, suspiciously) indisposed, they agree to leave their three kids in the care of a recommended replacement (Ireland’s Sarah Bolger, showing some range). She’s fun at first, but then begins to subject the kids to increasingly questionable, more sinister activities (I thought feeding the pet hamster to the pet snake was an original touch). It’s more uncomfortable than scary, really. But though it adds little to the Bad Babysitter genre, it plays with the inherent clichés in interesting ways. (82 min)