The black cat was a cat program in the Fifth and Sixth Matrix. One black cat was noticed by Neo as an example of déjà vu in the Matrix during the Hotel Ambush. One also passed Sati at the Reload at the end of the Fifth Matrix. It is not clear whether the same program controlled one or many cats, and whether the two black cats mentioned were the same or different entities.
Hotel Ambush
After being freed in the Fifth Matrix, Neo was taken by Morpheus to see the Oracle. Once they had spoken, Morpheus, Neo and the rest of the crew left to exit at the Heart O' The City Hotel, but as Cypher had betrayed his crew-mates, the Agents knew they were there, and waited until they were in the hotel to ambush them.
The black cat was in the hotel, and passed by the crew on the other side of a doorway as they were crossing a mezzanine of a stairwell on their way to the exit. Neo paused and noticed the cat as it shivered and continued walking past the doorway. He then turned to go on.
At this instant, the Agents changed the code of the hotel to brick up its external doors and windows in an attempt to trap the crew in the hotel. This caused a glitch in the Matrix, making the cat return to where it was a few seconds before.
Just before continuing on up the stairway, Neo looked back and noticed the cat shiver and walk past in exactly the same way as before. Neo assumed it was déjà vu, and mentioned it to the rest of the crew, who froze, and were alerted by this to the fact that the Agents had made a change and knew they were there.
Reload
In the wake of the battle between Neo and Smith at the end of the Fifth Matrix, the City was badly damaged. The programs and bluepills that Smith had cloned himself into had been returned to their original forms.
As the black cat was walking down a damaged street in the rain, the Matrix was reloaded to make the Sixth Matrix, causing the cat to disappear for a moment while the street was rebuilt and the rain stopped.
The cat ran over to Sati, who was lying on the street, and woke her. Sati greeted the cat, who ran off as she began to stand up.
Interpretation
- A black cat crossing your path is considered bad luck in western folk-lore.