Rex (Fallout: New Vegas)

Rex (full designation of Cyber-Hound Mk. III, LEO Support Model, Serial Number B955883) is a 209 year old cyberdog living in Freeside in 2281. He is owned by the King. He hates rats and will immediately go for one if he sees one. He also doesn't like hats, or people who wear them, and it's unknown why, although the King says it might be because "hat" rhymes with "rat".

Background
Rex is a cybernetic dog that has been around since pre-War times. He was used by the Denver Police Department. Since then, he's been the loyal pet of The King of The Kings in Freeside. Capable of sniffing out loot and taking a large amount of punishment. He can become your companion during the quest Nothin' But a Hound Dog. After the quest he will become permanent. When asked to get a new brain for Rex, if you ask the hound master in The Fort, he will ask the player where he found Rex as Caesar had one just like him, but he was lost in battle, and presumed dead.

Appearances
Rex appears in Fallout: New Vegas.