If an opponent uses a priority move (including moves boosted by Prankster or Gale Wings) that targets the Pokémon with Armor Tail or its allies, Armor Tail prevents the Pokémon from executing that move (PP is still consumed). When this occurs, the text "[Pokémon] cannot use [move>]" is displayed.
Moves that target all Pokémon (except Perish Song) and moves that target the opponent's side of the field cannot be blocked by Armor Tail, even if they become priority moves. Armor Tail has no effect on allies' priority moves.
Mold Breaker, Turboblaze, and Teravolt will ignore this Ability.
Priority moves called using Instruct retain their original priority and are blocked by Armor Tail. Non-priority moves called using Instruct with boosted priority (for example, if the Instruct-user has Prankster) similarly retain their original priority and are not blocked.
