4. The Invaders (1967–1968)

When architect David Vincent witnessed a flying saucer land near a deserted diner, he kicked off one of the most intense, paranoia-fueled dramas of the late 1960s. Produced by Quinn Martin, The Invaders ran for 43 episodes and presented a chilling premise—alien beings from a dying planet were already here, disguising themselves as ordinary humans to slowly infiltrate the highest levels of human society.

As documented by the show’s official entry, these extraterrestrials possessed a few distinct physical traits: they lacked a pulse, showed no emotion, and often exhibited a deformed fourth finger that could not bend.

When killed, they would glow red and disintegrate entirely, continuously leaving David Vincent without the physical proof he needed to convince a skeptical public. The show perfectly captured the Cold War anxieties of its era, and Roy Thinnes anchored the series with a genuinely compelling, determined performance.