This is great. Kids love it. But I have to say that adults love it too. The man used to teach elementary school and he introduced this to me before we were married. I got so excited about it. We used to go to parties, and I mean the adult kind of parties where you stay out late, drink too much, raise a ruckus and generally act like children. And I would raid the kitchen wherever we were and make this stuff. Imbibing adults really like it.
And now we know that the bug likes it too.
According to Instructables: Oobleck is a non-newtonian fluid. That is, it acts like a liquid when being poured, but like a solid when a force is acting on it. You can grab it and then it will ooze out of your hands. Make enough Oobleck and you can even walk on it!
Oobleck gets its name from the Dr. Seuss book Bartholomew and the Oobleck where a gooey green substance, Oobleck, fell from the sky and wreaked havoc in the kingdom. Here the Oobleck will be made in a bowl and will likely make a mess, but only because you can get carried away playing with it.
(I just love the internet. I did not know any of this before now.)
It really is a fun experiment and you probably have what you need in your cabinet now. Cornstarch and water. That's it. The ration is between 1:1.5 and 1:2, water to cornstarch. So 1 cup of water and between 1.5-2 cups of cornstarch. They used food coloring which would be very cool. We've only ever done straight white.
Make up a batch and act like a kid. Even if you don't have one.