hoist with own petard
hoist with one's own petard
Fig. to be harmed or disadvantaged by an action of one's own which was meant to harm someone else. (From a line in Shakespeare's Hamlet.) She intended to murder her brother but was hoist with her own petard when she ate the poisoned food intended for him. The vandals were hoist with their own petard when they tried to make an emergency call from the pay phone they had broken.
hoist with your own petardalso hoist on your own petard
to be harmed by something that was intended by you to harm someone else The most enjoyable moment in any action film occurs when the villain is hoist with his own petard.
Etymology: based on the literal meaning of hoist by your own petard (blown into the air by your own explosive device), an expression made popular in Shakespeare's play, â€œHamletâ€