 They have yellow blood.In "Smith and Jones" (2007) in Series 3, the Tenth Doctor (David Tennant) had never encountered the race on-screen before, but during the episode he repeatedly demonstrates considerable knowledge of them and their methods.The Judoon used an H2O Scoop to bring a hospital which held the Doctor and Martha Jones (Freema Agyeman) to the Moon where the Judoon could apprehend a criminal (species Plasmavore), which disguised itself as Florence Finnegan (Anne Reid).