Toho was churning out a steady stream of Godzilla films in the 50s, 60s and early 70s, they took a bit of a break after the release of 1975’s Terror of Mechagodzilla, and it wasn’t until nine years later that Godzilla returned. During that downtime, a few former Toho filmmakers got together and essentially made a Godzilla fan film, without the approval of Toho, titled Godzilla vs. Wolfman (poster seen at the top of this post). Much like Godzilla vs. Frankenstein, the film was centered on a giant-sized Wolfman doing battle with Godzilla.
Presumably because Toho didn’t give their approval to the project, Godzilla vs. Wolfman was never released in 1983, as planned, and in fact it still to this day hasn’t seen release. The film was completely shot, and footage has been shown at the annual Godzilla convention G-FEST, but as of now there are no plans for its release.