Film: Kronos (1957)
Location: Civilized area
Height/Weight: About as big as a large skyscraper.
Summary: Energy is what powers modern society. It is the potential source of 50 wars and a few more, and anyone will get it at any price. The beings beyond space certainly think so. Otherwise, they wouldn't send this giant sentinel to get it for them.
History: The aliens, presumably beings of pure energy themselves, had completely deprived themselves of their resources, so they saw it fit to just take it from other worlds, no questions asked. To do this, one possessed a scientist into shooting down their own saucer. As it turns out, this was a means to unleash Kronos, a gigantic war machine that would rob the world of all its energy, and grow stronger for it.
Notable Kills: Nothing special.
Final Fate: Eventually, the scientists figure out Kronos' primary weakness, and use it to cause the robot to quite literally eat itself by taking in its own energy, causing it to explode. While there most certainly will be more energy-nappers out there, we are at least prepared.
Powers/Abilities: With each portion of energy Kronos consumes, he grows larger and more powerful. So powerful he can withstand atomic blasts, shoot lightning, and send out sonic waves to bring down foes.
Weakness: If one can figure out how to reverse Kronos' polarity, the machine will begin to self-destruct.
Scariness Factor: 4-Kronos is a near unstoppable monolith of power, so chances of survival are slim. It doesn't help that it's rather slow, thus stretching out your town's inevitable doom. Not the most remarkable of appearances though.
Trivia: -This film was made in less than two weeks. Impressive!
-One of the scientists in the film, the one played by George O' Hanlon, would go on to voice George Jetson. No wonder nothing looks like Kronos in that show.