If Rapidash is your Active Pokémon and is damaged by an opponent's attack (even if Rapidash is Knocked Out), the Attacking Pokémon is now Burned.

Shooting Fire

Discard 2 Fire Energy attached to Rapidash and choose 1 of your opponent's Pokémon. This attack does 60 damage to that Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)