Quicksand is a mixture of sand and water that looks solid but acts like a liquid when you step on it. The sand grains are suspended in so much water that they can't support weight the way dry sand does. When pressure is applied, like from a footstep, the sand particles shift and flow, causing whatever stepped on it to sink.

Despite what you see in movies, quicksand rarely swallows people whole. You would need quicksand much deeper than a person is tall for that to happen, and such deep quicksand is extremely rare. What actually happens is that you sink partway in, usually up to your waist or chest, and then stop sinking because your body is less dense than the quicksand. The real danger can come from panic: thrashing around can make you sink faster. People who study quicksand say that a good way to escape is to lean back slowly and spread out your weight, almost like you're floating, then gradually work your way to solid ground.

Quicksand forms in places where water flows upward through sand, like near riverbanks, beaches, or marshes. The upward water flow prevents the sand grains from settling and packing together tightly. People also use quicksand metaphorically to describe any situation that gets worse the more you struggle against it, like when trying to argue your way out of trouble only makes the trouble deeper.