Batman Vs Godzilla

Batman vs. Godzilla (Battoman tai Gojira, lit. Batman Against Godzilla) is an unmade kaiju film that was planned to be released in 1966, as well as being a collaboration between Toho and an American film studio.

Why It Was Cancelled
Reasons are unknown.

Results
In 1966, Toho released the film Ebirah, Horror of the Deep, also known in North America as Godzilla vs. the Sea Monster.