Fun Fact: Quicksand is a colloid of water and sand, silt, or clay. This non-Newtonian fluid can look like a solid when undisturbed (think Oobleck), but can quickly lose viscosity when stepped on. Luckily, it is impossible for a human to sink entirely due to its higher density!
In the 60's, quicksand was a recurring element in movies and TV. In my mind it was a clear and present danger so I learned how to survive it (don't panic, lie on back to distribute weight). I was also afraid of the Bermuda Triangle, razor blades in candy bars, and Charles Manson.