Film: The Beast from 20,000 Fathoms (1953)
Location: Tundra/Ocean/Civilized area
Height/Weight: About half the size of a large building.
Summary: Before Godzilla, a different giant lizard made it to the modern day. While not as powerful or large, this beast from the land that time forgot took one Hell of a bite out of the Big Apple.
History: Somewhere in the polar icecaps, "Operation Experiment" (gee, nice name) was underway. And by that, we mean they dropped an atom bomb somewhere there. And surprise, a giant monster was sleeping there. This prehistoric monster, the Rhedosaurus, was driven by instinct to head towards the Hudson River, where its fossils were plentiful. Unfortunately, that meant utterly trashing all of New York to get there. And to make matters worse, his blood was contaminated with a contagious illness, making killing him the normal way about as effective as putting out fire with gasoline.
Notable Kills: Nothing special.
Final Fate: After tracking the beast down to Coney Island, a human manages to fire a radioactive isotope into the beast's neck wound (on a roller-coaster, no less). And with that, the Rhedosaurus is back on the extinct species list.
Powers/Abilities: Impervious to bullets, and holding in a nasty plague-like illness in his blood that can kill a man in seconds.
Weakness: Heavy artillery is the reckless way out, though a counter-weapon for the deadly blood works better, if you can find an open wound that is.
Scariness Factor: 4-Big and hungry, the Rhedosaurus is bad enough on his own. But then he came down with the prehistoric flu and made killing him normally an impossibility. Again, all of this before Godzilla.
Trivia: -The film is mostly based on Ray Bradburry's short story, "The Fog Horn", in which a sea monster repeatedly returns to a lighthouse after mistaking its noises for that of a potential mate. It's rather sad, really.
-The Rhedosaurus bears an uncanny resemblance to the tuatara, a lizard from New Zealand said to be the last surviving species of an order that died out millennia ago.