Actually, it's a little dry ice and water...but to my son, it was a ghost and he is fascinated by ghosts.
We received a shipment of meat and in the cooler was a bag of dry ice. So, I put it to good use and had some fun with the kids. I got out my large pot, put the dry ice in it (using gloves so I wouldn't get a freezer burn) and handed my son a cup of water and told him to pour it in.
There was so much amazement and wonder in both of my children as they watched the "smoke" grow and overflow the pot.
It was such a great activity to do with the kids. I don't think I ever would have just gone out to buy dry ice, but since we had some just laying around. I told this to a girlfriend of mine and she told me about something she saw at the Children's Museum in Austin, TX. They added a small amount (like a few drops) of dish soap and it apparently created, "smoke bubbles." When you popped the bubbles, you would then see the "smoke." Actually, the smoke is carbon dioxide, so if you decide to have any fun with dry ice, please do it in a well ventilated room. So, that fun experiment will be tried out the next time we end up with some dry ice just laying around.
I also completely forgot about doing the balloon experiment with it too. Place a small piece of dry ice in a latex balloon and as the dry ice transforms from a solid to a gas, it inflates the balloon.