Opportunist

Opportunist allows the Pokemon to automatically copy any stat boosts that an opponent applies to itself, introduced in Generation IX. Whenever an opposing Pokemon raises one of its stats through a move, ability, or item, the Opportunist user receives the same boost at the same magnitude without spending a turn.

The copying is immediate and mirrors exactly what the opponent gained -- if an opponent uses Swords Dance (+2 Attack), the Opportunist user also gets +2 Attack. This applies to all stat-raising effects including ability triggers like Speed Boost or Moody boosts, item activations like Weakness Policy, and self-boosting moves like Calm Mind or Dragon Dance. However, Opportunist only copies boosts, not drops -- if Moody raises one stat and lowers another, only the raise is copied.

Opportunist is the signature ability of Espathra, the Psychic-type Pokemon from Generation IX. In competitive play, it creates a powerful deterrent against setup sweepers -- any opponent that tries to boost in front of Espathra immediately gives it matching boosts for free. This forces opponents to either avoid boosting entirely or accept that the Espathra user will match their investment. Combined with Espathra's access to Stored Power (which scales with stat boosts), copied boosts can fuel devastating offensive power.