According to Stuart Galbraith's book Japanese Science Fiction, Fantasy and Horror Films, after GAMERA VS. ZIGRA was released, Daiei planned to produce another in the series of Gamera films, with the working title GAMERA TAI LEOMAN ("tai" translating into "against" for those wondering). However, due to the failure of ZIGRA among other things, Daiei soon went bankrupt, and the film was never made. Unfortunately, we here at UGMM know little else about the project beyond the name.

NOTE: Some sources cite information that this title was intended for an early version of the GAMERA VS. ZIGRA script. If this is correct, it is unknown if they went back to their original concept with the next film, or if it would be something else entirely.