Jonesy

Jonesy was a calico cat carried on the. It was a pet of someone onboard the Autumn and was onboard during the Battle of Reach and when the Autumn reached Installation 04. However, Jonesy's owner had lost him by then, although he put notices on the Bulletin Board to alert other personnel to the lost cat. Jonesy is assumed to have died during the Battle of Installation 04 either during the Covenant boarding, when the Autumn crashed, the Flood Invasion, or when John-117 and Cortana initiated a catastrophic wildcat destabilization that destroyed all of Installation 04.

Trivia

 * Jonesy is a reference to the cat Jonesy from the first two Alien films.
 * On the level "Crows Nest" in Halo 3, there is a pile of rubbish located near the toilets in the level. One of the pieces of rubbish is a note which is half covered up, but reads "Still missing my cat Jonesy".
 * A similar poster can half be seen in the rubbish on High Ground. You can see a picture of a cat and the word "missing" and "onesy" which is more than likely just "Jonesy".