I have been having experiences with, what I suspect, to be a ghost cat. For example, while resting one day, I felt my cat jump on the bed, pad over the bed and then lay on my feet. I even felt the sensation of purring vibrating on my feet. I thought it was so sweet because my cat rarely does that. I lifted my head to look and my cat was actually across the room staring intently at me, but I swear there was a cat laying on my my feet. This has happened two or three times now.
Tonight I was walking towards my house. It was dark night outside with no moonlight or stars and only the lamp at the end of our driveway gave us some light. We live in a rural area. My cat was acting very goofy and playful, he would hide in the bushes and pounce on me then I scream and laugh. We were in a fun mood. Suddenly he got still and his tail was fluffed out and tucked under him. He didn't move an inch. I looked where he was looking and I saw a black neighbourhood cat zip by me. It wasn't the black cat that I found noteworthy and startling, it was actually what followed that made my jaw drop. A white misty flash, about the same size of the fleeing cat, was chasing the black cat. The white mist just evaporated into the darkness as it passed me.
I have never heard or even considered animal ghosts or spirits before. There must be other experiences out there. I have had numerous cats in my life, yet I have no impression what cat this might be. Why would an animal ghost stick around and not "move on"?
Perhaps it was one of your prior cats, but maybe it wasn't. It's hard to say if he was giving you comfort or getting comfort from your presence, but perhaps it was even a cat who used to live in the house with prior owners who felt comfortable with you.
Maybe Triskaideka has it right and it is solar flares and the full moon making it easier for visitations. I've heard from police officers that they definitely see an increase in crime during a full moon.