"Mifunesaurus" (meaning "lizard from the Mifune Group (of rock formations)") is the name given to an as yet undescribed genus of dinosaur from the Late Cretaceous and is therefore a nomen nudum. It was a carnivorous theropod, probably a Tetanuran, which lived in what is now Japan during the Cenomanian stage of the early Late Cretaceous, around 95 million years ago (mya). The name was first mentioned by Hisa in 1985 and was discussed at greater length by Dong et al. in The Age of Dinosaurs in Japan and China (1990), where the animal was described as being large and like Megalosaurus.