This reminds me of the "There is a town in one of my PC's tummy" thread. That was WIN.

You could always stick the corpses of your victims enemies in there and put some fungus to degrade it...

It would actually be a really good deathtrap for gnomes !

"Hey look ! I got a whole ecosystem in my BoH ! Wanna check it out ? *bluff check optional*

Gnome: Sure !

5 minutes later: Cant breathe, air filled with spores..."