Hoist with own petard Fig. to be harmed or disadvantaged by an action of one's own which was meant to harm someone else. Based on the literal meaning of hoist by your own petard; blown into the air by your own explosive device. (From a line in Shakespeare's Hamlet.) More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.