Matango

A Japanese yacht on a day trip encounters a nasty storm that nearly capsizes it. The group arrive at a seemingly deserted island, with a seemingly endless forest of mushrooms. As the days pass, the group begins to grow restless as their supply of food stores start to run low. One night, as Kasai is raiding the food stores, he is attacked by a grotesque-looking man who promptly disappears after encountering the group, leading them to believe that something is very wrong with the island. They begin to suspect that the ship had been involved in some sort of nuclear testing of the polluted waters, forcing gross mutations on various objects