It's a folded newspaper. That's what "Ruby's" got under his arm. So, Jack Ruby showed up to the Oswald killing with a newspaper folded under his arm? Why would he bring that along? Check the sports while he was waiting for Oswald to come out? Keep track of how is IBM stock was doing? Ah, up a point. Or, did he figure that if the gun misfired, he could always roll up the newspaper and whack Oswald with it? Something is better than nothing.
So, what happened to the newspaper when he rushed Oswald? Didn't he have to drop it on the ground? Why wasn't it found? You know what happens to newspaper when it gets wet? Well, that's what's happening right now to the official story of the Oswald murder.