Willis O’Brien’s Frankenstein!
"O'Brien came up with a proposed treatment, King Kong vs. Frankenstein, where Kong would fight against a giant version of Frankenstein's monster in San Francisco. O'Brien took the project (which consisted of some concept art and a screenplay treatment) to RKO to secure permission to use the King Kong character. During this time the story was renamed King Kong vs. the Ginko when it was believed that Universal had the rights to the Frankenstein name (they actually only had the rights to the monster's makeup design). O'Brien was introduced to producer John Beck who promised to find a studio to make the film (at this point in time RKO was no longer a production company). Beck took the story treatment and had George Worthing Yates flesh it out into a screenplay. The story was slightly altered and the title changed to King Kong vs. Prometheus, returning the name to the original Frankenstein concept (The Modern Prometheus was the alternate name of Frankenstein in the original novel). Unfortunately, the cost of stop animation discouraged potential studios from putting the film into production. After shopping the script around overseas, Beck would eventually attract the interest of the Japanese studio Toho. Toho had long wanted to make a King Kong film and decided to replace the Frankenstein creature with their own monster Godzilla. They thought it would be the perfect way to celebrate their thirtieth year in production. John Beck's dealings with Willis O'Brien's project were done behind his back, and O'Brien was never credited for his idea. " - quote source. - Image source.
On the subject of Kong, here's a fantastic conceptual sketch.
And test footage of another never to be made Willis O'Brien classic stop motion monster..
Does anyone know what Willis O'Brien film the Monster Brains logo monster is from?