[BM] If it is alive/dead but the components thereof have not sufficiently decomposed to the point where it would be considered a mineral by geological standards, then it's animal and/or vegetable. A cricket ball, e.g. is both animal and vegetable. Bone, if that were the object in question, I would list as animal and mineral.

Or they just found the idea of Darren and Derren on stage at the same time to be too disturbing...

[BM] All sounds a bit quantum, to me.
What you're trying to do is draw definite lines along fuzzy boundaries, which looks OK from a distance but when you look closely, well, aren't.

[Darren] "Only a game"? You won't win anything with an attitude like that, my lad!

We had the same argument over SARS when that was a subject -- was it an animal, vegetable, or mineral? A virus is a non-cellular collection of ribonucleic acids which merely attaches to an unlucky living cell and sort-of-passively uses the cell's contents to propagate itself.

I'd claim it's a mineral, but others would have a valid argument otherwise.

And what about mushrooms?