Honjou o Awarashita Kioku Dorobou no Saigo Gyakushuu

Luffy returns and knocks some sense into Zoro. Cornered, the sea horse spreads illusions of the people in their memories to distract them. It steals their complete memories and claims that it has become a Sennenryu. Luffy defeats it and returns all the memories but the townspeople are convinced they are the memory stealers.