Truant
Gen IIISkips every second turn.
Truant in Battle
Truant forces a Pokémon to alternate between acting and loafing around, creating a predictable pattern where the Pokémon can only use moves every other turn. When loafing around, the Pokémon does nothing at all, similar to being fully paralyzed or flinching. This limitation applies regardless of whether the Pokémon successfully uses a move or fails due to paralysis, sleep, or other conditions - the attempt itself triggers the loafing period. The ability interacts uniquely with various move types, cutting off multi-turn attacks like Rollout or Bide when loafing begins, while moves forced by effects like Outrage or Encore continue their duration normally.
The most notable competitive implication involves Slaking, whose massive base 670 stat total is balanced entirely by this crippling ability. Despite incredible offensive potential with 160 base Attack, Slaking sees virtually no serious competitive play because opponents can easily exploit its forced downtime. The ability has some unusual interactions with status conditions - confused Pokémon cannot hurt themselves while loafing, and sleep or freeze delays the loafing cycle until the Pokémon actually attempts to move again.
Interestingly, while Truant cannot be replaced through Worry Seed, it can be circumvented through Gastro Acid, Role Play, or Skill Swap. This has led to niche strategies involving removing Slaking's Truant in doubles formats, though such setups remain largely theoretical due to their complexity and vulnerability.