The Curse of the Black Spot by a Siren-like creature who marks people with black spots on their palms after they are injured and appears to disintegrate them with her touch after putting them in a trance. Rory Williams receives a cut during a tussle with the pirates, and finds a black spot on his hand, but is prevented from succumbing to the song of the Siren by Amy Pond and the Doctor. Surmising the Siren is using water as a portal, the Doctor instructs the crew to seek refuge in the ship's dry magazine. There, they find Toby Avery, the son of the ship's captain
The Seven Crystal Balls for a moment into Haddock's shoes and to be autobiographical". Jean-Marc Lofficier and Randy Lofficier believed that the two-story arc represents "one more leap forward in Hergé's graphic and narrative skills" as a result of the transition to full colour double pages as the initial means of publication. They noted that "The Seven Crystal Balls" is "bathed in the surreal atmosphere that Hergé knew how to create so well", with Tintin confronting "a dark and oppressive force" that was "worthy of a Hammer film." They asserted that the character of Professor Tarragon was "to archaeology what Haddock is to the