As long as Abomasnow is your Active Pokémon, any damage done to your Pokémon by an opponent's attack is reduced by 20 (after applying Weakness and Resistance).

Does 20 damage to each of your opponent's Benched Pokémon, excluding Pokémon and Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)

If Abomasnow evolved from Snover during this turn, the Defending Pokémon is now Paralyzed.