Michael Fassbender pulls double duty in his new film Alien: Covenant [1]. Not only does he reprise his role as David, the uncanny android who really messes things up in Prometheus [2], but he also portrays Walter, a new and improved version of the former. We sat down with Michael (and director Ridley Scott) to get the details on how he managed those scenes with himself [3] and mastered those two instruments [4]. Hint: it involves a lot of careful choreography . . . and some slapping.