Stanley is a very well read kitty. He is pondering life. And yes, that is a harmonica he’s holding.
Note: I was going to remove it, but I didn’t… he has a stain on his hind leg that you can see. He was homeless a few weeks ago and the stain came with him. It is fading, but I am assuming it is rust. I’ve tried washing it. Guess he found something rusty to sleep on when he was hitting the streets!