5. Bob, 'Twin Peaks'
Behold, the answer to the question: "Who killed Laura Palmer?" As a being from the extradimensional vortex of evil with the red curtains and zig-zag flooring that was Twin Peaks' visual signature, Bob is a kind of demon who relies on possession to perpetrate his horrible crimes. And while we won't tell you whom he took over to commit the murder at the heart of David Lynch and Mark Frost's still-peerless horror-mystery masterpiece, we will say that his every on-screen appearance, from the truly shocking reveal on down, is the stuff of nightmares. Actor Frank Silva, who screamed and laughed his way through the part like he was possessed, was just a crew member until a couple of coincidental glimpses of him on set led Lynch to create the character for him. The result: the greatest ghoul in the history of television, hands down.