The best defense against a chameleon from beyond the stars is a tin-foil hat. At least that's what Macaulay Culkin's autistic brother thinks, so Joaquin Phoenix and Abigail Breslin decide to go along with it in Signs. Culkin's encyclopedic knowledge of alien invasion tactics is unsettling and eerie. So it's a let-down when the monster finally shows up and blends his skin with the boy's flannel shirt. Both types of paranoia, the silly hats and the smart reasoning, show why M. Night Shyamalan was such a big deal for a while. And why alien invaders can still freak us out.