Landing! The All-Female Island, Amazon Lily

Three days have passed since the incident at Sabaody Archipelago. Having been hit by Kuma, Luffy is teleported to an unknown island. Searching for food, he comes across some unknown mushrooms, and eats them. Unfortunately, these mushrooms are "mushrooms-growing-on-body-mushrooms", and as Luffy goes to sleep, mushrooms start growing on his body. He is discovered by a trio of amazon women who take him to their city in order to cure him, but during the cleaning process, it's discovered that Luffy, unlike everyone else on the island, is a man.