A Judoon officer
A Judoon unmasked
The Judoon are a race of humanoid Rhino type species. They normally employed as a type of extraterrestrial police force. They are large and strong but not very intelligent. They are good for hunting down and catching wanted criminals such as the Slitheen. Although they are not villains that are dangerous, they attack first and ask questions later. The tenth Doctor encountered a group of Judoon when they teleported a hospital he was in when they were tracking down an alien criminal. Sarah Jane Smith with her son Luke and his friends encountered one when he crash landed on Earth with a prisoner. Some Judoon were also part of the alliance which trapped the Eleventh Doctor.