Jonesy

Jonesy is the supposed name of a calico cat aboard the. It was probably a pet of someone on board the Autumn and was on board during the Battle of Reach and when the Autumn reached Installation 04.

However, Jonesy's owner had lost her by then, although he/she put notices on the bulletin board to alert other personnel to the lost cat. Jonesy is assumed to have died either during the Battle of Installation 04, during the Covenant boarding, when the Autumn crashed, the Flood Invasion, or when John-117 and Cortana initiated the catastrophic destabilization of the Pillar of Autumn's engines that destroyed Installation 04.

In Halo 3, there are posters for a cat by the name of Jonesy, with an apparent silhouette of a cat in the bottom right hand side of the poster.

Trivia

 * Jonesy is a reference to Ellen Ripley's cat of the same name on the commercial towing ship, the Nostromo, from the movie franchise Alien. Many aspects of Halo were inspired by elements from the Alien franchise.
 * The poster can be seen on several other boards throughout the Halo: Combat Evolved level, The Pillar of Autumn.
 * On the level Crow's Nest in Halo 3, there is a pile of garbage 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". This is most likely a reference, a homage, or another easter egg.
 * A similar poster can half be seen in the trash on the the left side of Foundry facing the fan. A picture of a cat can be seen and the word "missing" and "nesey", which is believed to read "Jonesey".
 * In the remake of the game, on several message boards it is stated that a cat was found.