The name is a reference to the Dr. Seuss book "Bartholomew and the Oobleck", published in 1949. I remember reading it as a child, probably around the same time

The name is a reference to the Dr. Seuss book "Bartholomew and the Oobleck", published in 1949. I remember reading it as a child, probably around the same time I mixed up a batch of the non-newtonian cornstarch mixture, though I can't remember whether the name had become associated with the substance at that time or whether we called it something else. In any case, I think it is likely that the current use of "oobleck" predates the existence of YouTube.