Gang Up

Gang Up is a pokémon ability that four pokémon have.

In Battle
When a pokémon with Gang Up is fighting and another pokémon with Gang Up is in the party, they both fight the ennemy pokémon in a unloyal 2 vs 1.

If no other Pokémon in the party has the ability Gang Up or a pokémon with the ability is fainted, this ability does nothing.

Outside Of Battle
If a Pokémon with Gang Up is in the first place in the party (even if fainted), then there is a 30% chance the game will force an encounter with an Dark-type Pokémon, if one is possible.