I Am an Alien (3), originally The Alien's Repayment! in the WSJ release, is the three hundred eightieth chapter of the JoJo's Bizarre Adventure manga. It is also the one hundred fifteenth chapter of Diamond Is Unbreakable.
Summary
Mikitaka (who is now a pair of sneakers being worn by Josuke Higashikata) forcefully transported Josuke onto the roof. As a result, Josuke summons Crazy Diamond and pretends to punch the alien, asking him what he wants. Mikitaka doesn't react to the Stand, making Josuke believe that he isn't a Stand user but indeed an alien possessing powers. Taken aback by the revelation, Josuke thinks on what he needs to do, while Mikitaka insists on rewarding him for "rescuing" him from the siren.
Josuke sees a Kameyu Department Store catalogue and has the idea to use Mikitaka's shapeshifting ability to transform into a casino die. For Mikitaka's first attempt, he transforms into a giant die with two sides both showing five dots. Once Josuke lectures the alien on how a die properly looks, he tries rolling the die, which tickles Mikitaka and also gives him motion sickness. Josuke then spends some time practicing so that Mikitaka could give a desirable result for any dice roll. He plans to get rich by ripping off Rohan Kishibe of his money by cheating on a game of dice.