<Tr> <Td_colspan="2"> Lost (season 6) List of Lost episodes </Td> </Tr> <P> "Across the Sea" is the 15th episode of the American Broadcasting Company's sixth season of the serial drama television series Lost and 118th episode overall . The episode aired on May 11, 2010, on ABC in the United States . The episode was written by Carlton Cuse & Damon Lindelof and directed by Tucker Gates . The episode is centered on Jacob and The Man in Black . This episode is the second in the season that does not feature a "flash - sideways ." </P> <P> The episode, unlike most Lost episodes, does not divide its time between two different time settings, but takes place entirely in the past, except for a brief scene at the end from the season one episode "House of the Rising Sun ." It depicts the origins of the characters of Jacob (Mark Pellegrino) and his brother, The Man in Black (Titus Welliver), and how they came to be on the island . It also reveals the identities of the corpses discovered in the cave in "House of the Rising Sun ." None of the series regulars appear in the episode, except in the flashback sequence, making it the only episode of the series in which this occurs . </P> <P> This is the only episode where the Man in Black appears in his original, human form . In all of his other appearances, he is either in his smoke form or the smoke in the form of a dead person . Although he appears in his own form in "The Incident" and "Ab Aeterno", this was an imitation of his original form which by that point was dead . </P>

Who plays jacob as a kid in lost