Khellians were humanoids with scaly skin and heads like crocodiles.
Biology
Despite their similar appearances, they had varied personalities. (PROSE: Judgement of the Judoon)
History
A group of Khellians attacked a colony ship in the 29th century and forced the hand of the ships leader, Auntie into giving them cryogenically frozen human colonists for food. The majority of the Khellians were destroyed when the Fifth Doctor destroyed the colony ship. The leader of the Khellians survived the explosion and attempted the hunt down the Doctor, during the hunt, the leader ate Auntie. The leader was killed when Auntie detonated an explosive device inside his stomach. (AUDIO: Three's a Crowd)