I've watched cats get off-the-ground-and-in-to-the-air-like-a-cyclone-wound-up batting an apple around the floor. You have to wonder what thoughts are whirring in and around their tiny processors. And although I've never witnessed it, I bet it's not unusual for one of these psychos, in a full on frenzy, to end up having taken bite taken out of an apple at some point. And if a bite is taken and ingested, what happens?
As it turns out cats can eat a slice or two of apple now and again without harm, but those apple seeds are killers. Unbeknownst to me, apple seeds contain cyanide. They contain only a small amount so they won't harm humans, but cats are too small to handle them. I find it unlikely however, that the attention span of said cat will get them that far into an apple core anyway, no offense.