quicksand

1. A bed of loose sand mixed with water forming a soft shifting mass that yields easily to pressure and tends to engulf any object resting on its surface.
2. A place or situation into which entry can be swift and sudden but from which extrication can be difficult or impossible. Often used in the plural: “This theory of the future entrapped [them] in the quicksands of Vietnam” (Arthur M. Schlesinger, Jr.)

Origin:

Origin: Middle English quyksond, living sand

Origin: : quick, quyk, living; see quick

Origin: + sand, sond, sand; see sand