The Rhinoceros Creatures Judoon are Police of the Universe.
The Judoon are a Species of Rhino working for The Shadow Ploclamation which are Police. They first started by trying to find a Plasmavore but they took the whole Royal Hope Hospital up to the Moon. They looked and looked and killed one of her Slabs. They disintegrated her and left the Hospital to die. But the Doctor Saved the day and everybody lived.
They then were asked to help the Doctor against the Daleks and Davros because they were invading a Level 5 Planet Earth. The Judoon were going to go with him but he left them and then they never trusted the Doctor as he had to hand over his Tardis. The Shadow Architect got furious with the Doctor and if she did so did the Judoon.
The Judoon were with the Daleks, Cybermen, Autons and Sontarans at the Pandorica which they helped put the Doctor into Pandorica Box to help save the Universe from the Doctor.
The Judoon have appeared in Series 3: Smith and Jones
Series 4: The Stolen Earth
Series 5: The Pandorica Opens