As long as Turtwig Gym Leader's remaining HP is 60 or less, each of Turtwig [GL]'s attacks does 30 more damage to the Active Pokémon (before applying Weakness and Resistance).
Attack: Giga Drain
Damage: 30
After your attack, remove from Turtwig Gym Leader the number of damage counters equal to the damage you did to the Defending Pokémon.