Change your preferences here.
When this Pokémon is hit by a Fire-type move, it takes no damage, and all Fire-type moves used by this Pokémon deal 50% more damage. While subsequent hits by Fire-type moves will deal no damage, they will not provide a further increase in the damage of Fire-type attacks. Will-O-Wisp also activates Flash Fire, even through a Substitute; however, Flash Fire is not activated through Protect. If a frozen Pokemon is hit by a Fire-type attack, it will be defrosted and take damage without boosting Flash Fire. The power boost granted by Flash Fire is lost upon switching out.