Sea monster

Sea monster was an umbrella term for mythological monsters which resided in the seas. Donna Noble investigated sea monsters in the hopes of finding the Tenth Doctor. (TV: Partners in Crime)

Creatures simply described as "sea monsters" were among the obstacles failed by Anti-Dalek Force agents and the Dalek extraction team as they attempted to reach the Dalek Emperor who was stranded on a rocky island in the middle of a "wild sea" on an unidentified planet. (GAME: )