Jonathan Moran
Jonathan Moran was the commanding officer of the Drum. He was scorched by rocket engines and transformed into a ghost by Prentis.
His ghostly form stalked the crew throughout the night, following them to the Faraday cage, which prevented the ghosts from entering. However, when the Twelfth Doctor and Clara Oswald arrived, Moran and Prentis went after them, attacking them with weapons but ultimately retreating through a wall. When the "day mode" of the base flashed on, however, Moran and Prentis dissipated, allowing the crew to move freely throughout the base without being attacked.
When the base unexpectedly went into night mode again, Moran and Prentis drowned crewmember Richard Pritchard and converted him into a ghost.
It was then that the Doctor decided to set a trap for the ghosts. He sent each crewmember except for Cass and Alice O'Donnell (who he kept to man the controls) out into the base to lead the ghosts into a trap in the Faraday cage. The trap succeeded and the Doctor went into the cage himself to speak to the ghosts, and Cass figured out what the ghosts were all whispering in unison.
Later, the ghosts figured out how to override the controls and they flooded the base. The Doctor, O'Donnell and Bennet, however, escaped from the ghosts, while Clara, Cass and Lunn were trapped in the base behind the flood doors. (TV: Under the Lake)
