Oobleck is a non-Newtonian fluid( meaning its viscosity changes with stress added to it).
Ex: Tomato Sauce, Cream, honey, and Oobleck.
Oobleck is a mixture of water and cornstarch.
The liquids I have mentioned have different properties that change due to stress; Oobleck becomes more viscous or thick, even to the point of acting more like a semi-solid than a liquid; The other non-Newtonian fluids I have mentioned; I will not say what their properties are, but you can find out at this website.
And here is a video by TheBackyardScientist talking about Oobleck and doing experiments with it.