Judoon

The Judoon were a race of rhinocerid humanoids frequently employed as a mercenary police force. They were similar to robots as they carried out their tasks without regard for the consequences of their actions, They first appear in the Doctor Who episode called Smith and Jones.

Appearance in episodes
Smith and Jones (first appearance)

The Stolen Earth

The End of Time

The Pandorica Opens

A Good Man Goes to War

The God Complex (picture)