Huge brown hole in apple with cobwebs inside?

So today I was eating an apple from the Kiku brand. I had my unlucky first bite and there was a huge hole underneath the perfectly fine looking skin. The hole was browned around and had cobwebs or some silk inside of it. Everything looked like mush inside and went all the way to the side of the core.

I'd have to say it was at least an inch by an inch wide on a slightly bigger than average size apples. Does anyone know what I happened to eat?