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.

Bugs

 * On occasion, while walking around Camp McCarran and NCRCF, all NPCs (including another companion) will begin shooting at Rex, and Rex will attack back. None will appear hostile and shooting will cease once Rex is unconscious. When Rex wakes up, it will continue to occur until the player leaves. (A similar bug can occur with ED-E, it seems)


 * After replacing Rex's brain he may become immobile.


 * When asked to wait, Rex may disappear after the player leaves the area. Npcs will still make remarks to you as if he was there.This can be fixed by waiting 3-5 days.If this happens during "Nothin but a Hound Dog" you will have to wait to be able to finish guess who i saw today, if Rex is not returned by the time Lily needs to be tested and you have gotten a brain Lilly will not be tested untill Rex receives his new brain.


 * Currently, Rex has a bugged dialogue-script at the end of "Nothin' but a Hound Dog". After his brain is transplanted, Rex will come forward to you and the game will freeze. (Needs confirmation/details? Seems like transplants are working)


 * After replacing Rex's brain with Lupa's, his health was set to 540/440 (440/440 being the default). Upon taking damage that reduced his health beneath 440, it could not be restored past 440. This obviously made Lupa's brain's "Blood of the Legion" perk effectively useless.


 * During combat, Rex might chaotically run around from-and-to foes while not attack. This happens to me 9 out of 10 times [PC VERSION needs further confirmation]


 * When knocked unconscious by the Courier, at times Rex will be randomly shot hundreds of feet into the air (Similar to a grenade going off).


 * If Rex is told to wait for you at the Lucky 38 he may not be found there when you return but he might be found back with the king and when approached will start running back to the Lucky 38 (confirmed on PS3, Xbox and PC)