Daikū Maryū Gaiking (Great Sky Demon Dragon Gaiking) was a Super Robot mecha anime series produced by Toei Animation, credited as an original idea by Akio Sugino. However, in reality the original idea was Go Nagai's. Toei deliberately took Nagai out of the credits in order to avoid paying him royalties. Because of that, Nagai sued Toei and refused to collaborate with them for many years. The legal battle lasted over a decade. Nagai himself confirmed that he was the creator of Gaiking at the 2007 Naples Comicon.