First appearance: Son of Godzilla (1967)
A real-life black widow spider is scary. A tarantula is scarier. The huge spiders in The Hobbit are really, really scary. The huger spiders in Eight-Legged Freaks are terrifying. Kumonga is a spider who stands about 150 feet tall. He might wrap you in a web and kill you at his leisure, or if he's in a rush, he'll just stab you with the razor-sharp points at the end of each leg.
This is an important lesson in the difference between Japanese and American schlock. In America, a spider exposed to radiation bites Peter Parker and turns him into the crime-fighter Spider-Man. In Japan, a spider exposed to radiation grows to roughly the size of the Houston Astrodome and sets about destroying things.