Ten times as big as a man!!
So went the theme song to the 1966 Rankin/Bass cartoon featuring a somewhat more user friendly version of the Willis O'Brien creation.
Giant ape afficionados are certainly familiar with the Kong that Willis created for the 1938 classic. His animated monsters are justly famous.
But they may be surprised to learn that O'Brien hoped to produce a movie pitting Kong against Frankenstein. He was unable to find a backer in the US, but he sold the script, "King Kong vs Prometheus" to Toho Studios in Japan.

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These images are from an exhibit of Willis O'Brien artifacts.