hoist by one's own petard
- For tis the sport to haue the enginer / Hoist with his owne petar.
- (idiomatic) To be hurt or destroyed by one's own plot or device intended for another; to be "blown up by one's own bomb".
- He has no one to blame but himself; he was hoisted by his own petard.
- In the US, the forms in "hoisted" are about as common as the forms in "hoist", in contrast to other usage of the past and past participle in which "hoisted" is fifteen times more common. Similarly in the UK, "hoisted" is far more common than "hoist" for general use of the verb, but in this specific idiom both forms are seen; a writer might be more likely to use "hoisted" when thinking of the hoisting as an event that occurred to the victim, and "hoist" when thinking of it as a state in which the victim finds themself ("She's been hoisted by..." / "Now she's hoist by...").
be hurt by one's own plot