What are Hidden Abilities in Pokémon Black and White?

Every Pokémon species carries abilities, the passive traits that shape a battle, and from the beginning each species had one, or a choice of two. Generation V quietly added a third slot for most species: a Hidden Ability, invisible in normal play, which no wild or bred Pokémon in Unova would ever show. The slot existed in every Black and White cartridge from launch, but the keys to it were kept online.

The main key was the Dream World. Every Pokémon befriended there and brought home through the Entralink arrived with its Hidden Ability, which turned the browser game's gentle befriending loop into serious collecting: a Vulpix with Drought, a Poliwag whose evolution Politoed would carry Drizzle, rain and sun on demand from Pokémon nobody had feared. Those two in particular rearranged competitive battling overnight, because permanent weather had previously belonged to legendary Pokémon alone.

The sequels added offline doors. Black 2 and White 2 scattered Hidden Grottoes across Unova, hollow trees and clearings where a Pokémon with its Hidden Ability waited, respawning on a timer, and the 3DS companion app Dream Radar sent over its catches the same way, Hidden Ability included, in Dream Balls.

When the Dream World closed in January 2014, Generation V's supply of many Hidden Abilities closed with it, one reason Dream World specimens remain distinct in a collection's data today. The hidden slot itself never left: it became a permanent part of the series, a third talent every species quietly carries, first dealt out by a website that no longer exists.