I build unusual props for people and have a friend with a pretty awesome cabinet of curiosities, or wunderkammer. In it there are taxidermy (or mounted) animals, skulls, weird occult artifacts, some glass eyes and lots of strange knicknacks from around the world. When he found an expired mouse in his shop he brought it over and asked to have it displayed in a bell jar.
Fortunately the cadaverous murine had already had time to fully deflate and was dry as a bone. I simply took a pre-existing butterfly-in-a-bell jar display that I had and swapped out with the mouse. It is really quite hideous (it reminds me of Mike Mignola's zombie drawings).