Serene Grace will double the chance of a move having an additional effect. For example, Psychic will have a 20% chance of lowering the target's Special Defense stat instead of its usual 10% chance, and Rock Smash will always lower an opponent's Defense by 1 level, as opposed to having a 50% chance of doing so. The 10% flinch chance due to King's Rock and Razor Fang is unaffected by Serene Grace. Serene Grace has no effect on status moves.
Although the following moves are affected by the Ability, they currently cannot be learned by any Pokémon with Serene Grace. They may, however, be called via Metronome, Mirror Move, Copycat, or Mimic, or be used by a Pokémon that gained Serene Grace by Trace or a move such as Skill Swap or Role Play.