Sorry. Finger slipped.
The villain's own weapon or malicious plan is the cause of his downfall and/or death. This could be something as big as a Mad Scientist
who creates monsters and/or a Weapon of Mass Destruction
getting killed by his own creation, or as small as a prankster accidentally setting off his own trap.
In media intended for young children, it is often a Death by Irony
that releases the hero from the unpleasantness of actually killing their enemy; a more specific type of Self-Disposing Villain
If the hero
is not responsible for the death in any way, it can also be a Karmic Death
A "petard" is an explosive device (basically a bucket full of gunpowder) intended to demolish gates and fortified walls; being too close to the detonating explosive could well toss the engineers who planted it into the air. Thus, this term literally means "Blown into the air by one's own bomb" and was first coined
by William Shakespeare
If an Eldritch Abomination
, God of Evil
or otherwise supernatural evil entity gets Punched Out
by the same powers it gave, you have a Faustian Rebellion
in action. If it's an Ancient Conspiracy
, Government Conspiracy
or other organisation whose Applied Phlebotinum
is empowering the one who will bring them down, you have a Phlebotinum Rebel
. If it's a Mook
, long abused, who finally snaps and turns against him at the last moment, it's The Dog Bites Back
. If it's a Video Game
boss whose attacks can be redirected back at them, it's Tactical Suicide Boss
. Gone Horribly Right
is a sub-trope where a Super Prototype
works too well, destroying the person or persons who created it and/or threatening the world/galaxy/universe. If it's a vehicle that you just stole, it's Vehicular Turnabout
Compare Nice Job Fixing It, Villain
and Beat Them at Their Own Game
(a video game variation on this). The Streisand Effect
is a subtrope of this, when the petard is censorship.
As this is often a Death Trope, all Spoilers will be unmarked ahead. Beware.