The mystery begins near an American Air Force base in Manitoba, where unexplainable deaths are somehow connected to the base's atomic reactor, which is being used to power an experiment in advanced long-distance radar. Thompson (who later starred in the TV series Daktari) plays Major Cummings, who discovers that the lethal monsters--slurping, unseen "mental vampires"--are actually the horrific byproduct of thought-control experiments conducted by hapless, retired professor (echoes of Forbidden Planet's "monster from the Id"). Once visible, the fiendish brains are everywhere, attacking our heroes from every angle (in a scene that may have inspired Night of the Living Dead), and sputtering puddles of blood when riddled by bullets. This climactic scene--a triumph of latex rubber fiends, eerie sound effects, and stop-motion animation--was a gory breakthrough in 1958, and it's still a worthy precursor to every gross-out monster movie that followed in its trendsetting wake. Beware the faceless fiends! --Jeff Shannon