"mystery fruit" news and stories

OK, all you pomologists out there, I have a little challenge for you. Last weekend, I had my first encounter with the fruit you see here. It was unique, to say the least. I want to see how many of you can identify it. As a hint, I'll say that over the course of one week, it ripened from the color and texture of a Granny Smith apple to the soft, dark blob you see here. This is, I'm told, when it is ready to eat.

Just post your guesses in the comments. The winner will receive the undying admiration of their Slashfood peers. Later today, I'll post the answer, as well as another picture of the fruit after it has been cut open.