Pickle jar and looking for ideas. My first thought is some kind of floating head thing like the Governer used to have.

brain mold.
jello.
eggs as eyeballs. (I use olives as the iris)




Or you could try your whittling skills and buy a large cauliflower, shape it like conjoined animal fetus'.
Or just an old wig and mask in much fluid, Hannibal Lecter style.
Or you could put it on its side and make it a dedicated cat sit.
Ant farm.
Flesh eating bug farm.
Succulent garden.
Massive Lava Lamp.
Butterfly farm.
Poison dart frog habitat.
Have you pickled stuff yet?

I have an enormous...

Camera Lens. 

With fond memories of a Robin Williams improv segment where he took someone's SLR, positioned it at crotch level with the lens facing out, closed his eyes, grabbed the lens and yelled "Focus!  Focus!".