Look at the 7 cards from the top of your deck. Choose 1 card you find there, show it to your opponent, and put it into your hand. Put the remaining cards back on top of your deck. Shuffle your deck afterward.
Choose 1 of your opponent's Pokémon. This attack does 20 damage to that Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.) Then, remove from Manaphy the number of damage counters equal to the damage you did to that Pokémon.