pitfall

An unapparent source of trouble or danger; a hidden hazard.

A concealed hole in the ground that serves as a trap.

To lead into a pitfall; insnare.

A pit into which an animal may fall unawares, the opening being so covered as to escape observation.

Hence Figuratively, any concealed danger or source of disaster.

A pit deceitfully covered to entrap wild beasts or men; a trap of any kind.

a potential problem, hazard, or danger that is easily encountered but not immediately obvious.

An anti-pattern.

a trap in the form of a concealed hole

an unforeseen or unexpected or surprising difficulty