I seem to remember a line from a play or musical--"He's been strung up on his own petard!" What's that from?
Actually, it's from HAMLET:
There's letters seal'd: and my two schoolfellows,
Whom I will trust as I will adders fang'd,
They bear the mandate; they must sweep my way
And marshal me to knavery. Let it work;
For 'tis the sport to have the engineer
Hoist with his own petar: and 't shall go hard
But I will delve one yard below their mines
And blow them at the moon: O, 'tis most sweet,
When in one line two crafts directly meet.