By photoshopping a pair of mirror-flipped profile-shots of your face onto either side of a full-on shot, you can make a gimmicked photo that, when curled and placed in a jar of water, creates a convincing illusion of your head in a jar. Mikeasaurus's Instructable has easy-to-follow instructions for making your own.
You'll need a jar large enough to hold your picture. I got this 5 litre glass jar at my local hardware store for $15.
Filling the jar about halfway with water, I used a mix of yellow, orange, and green liquid food dye I tinted the water to resemble a preserving solution. Just like in the vintage science fiction movies.
Curling the laminated printout to fit through the jar neck the sheet was inserted, the jar was then topped off with water until full. The jar was then sealed. The head in a jar was now ready to be placed inside the fridge to prank hungry foragers.
Since the solution reminded me of brine solution I decided to add a few hard boiled eggs to my head jar for fun.