Non-Newtonian fluids are liquids that are sort of solid but also sort of liquid or a little of both.
The Backyard Scientist filled up balloons with non-Newtonian fluids and took a chainsaw through them, shot a BB-gun at them, and fired off a golf ball cannon at them too. He wanted to compare how non-Newtonian fluid would react vs regular water in the same situation. Let’s just say the non-Newtonian fluid explosions were so much better (and they acted like a solid).
Watch the video below to see how these materials react: