quicksand

Sand that is mixed with water in a collected mass and yields easily to pressure so that objects on its surface tend to sink and become engulfed.

A place or situation into which entry can be swift and sudden but from which extrication can be difficult or impossible.

A movable sand-bank in a sea, lake, or river; a large mass of loose or moving sand mixed with water formed on many sea-coasts, at the mouths and in the channels of rivers, etc., sometimes dangerous to vessels, and especially to travelers.

To catch in a quicksand.

To cover with quicksands: as, a quicksanded coast.

Sand easily moved or readily yielding to pressure; especially, a deep mass of loose or moving sand mixed with water, sometimes found at the mouth of a river or along some coasts, and very dangerous, from the difficulty of extricating a person who begins sinking into it.

Wet sand that things readily sink in, often found near rivers or coasts

Anything that pulls one down or buries one metaphorically

a treacherous situation that tends to entrap and destroy

a pit filled with loose wet sand into which objects are sucked down