Google struggles to help when you cannot tell it exactly what it is, or what it is called, so if you guys would help i'll... kiss you full on the mouth.
When i was a kid I had this hour glass type thing that had pruple goo or slime in it. It had two separate chambers and was about the size of a coke can, maybe a little bigger, and there was a mixture of the thick viscous fluid and air, i guess. If you turned it upside down it'd act like a lava lamp and the bubbles of air would slowly move through the liquid to the top and you could change the size of the bubbles by tilting it.
It looked like this: http://i53.tinypic.com/rwq3p3.jpg