Aftermath

Aftermath is an ability introduced in the fourth generation. It causes damage to the foe landing landing the hit that knockouts the Pokémon.

Effect
If a Pokémon with Aftermath faints from a contact move, the attacking Pokémon loses a quarter of its maximum health. Aftermath does not activate if a Pokémon with Damp is on the field.

In the Pokémon Mystery Dungeon series, occasionally if the Pokémon with this ability faints, it causes a blast similar to explosion, taking away half the health of teammates in its radius and 40 HP of hostile Pokémon.

Pokémon with Aftermath

 * Drifloon
 * Drifblim
 * Stunky
 * Skuntank

As a Hidden Ability

 * Voltorb
 * Electrode
 * Trubbish
 * Garbodor

Trivia

 * All Pokémon that are able to have this ability can learn Explosion. Its name in Japanese is more along the lines of induced explosion which explains why Damp prevents Aftermath.