You wouldn’t want to mess with the Judoon. This mercenary police force regularly work for the Shadow Proclamation. Stocky in build with rhinoceros-like heads, these powerful creatures are determined and single-minded in enforcing their missions.
The Judoon have no authority on Earth so when a dangerous Plasmavore criminal fled there, they transferred the entire hospital building where it was hiding to the moon using an H2O scoop. When a patient smashed a vase over one of the Judoon, they charged him with physical assault, found him guilty on the spot and executed him instantly with an energy weapon.
The Doctor has had a varied relationship with the Judoon. “Interplanetary thugs” is his description of them. While they are amidst many of the Doctor’s enemies when he is locked inside the Pandorica, they later stand with the Doctor’s army in the Battle of Demon’s Run.