For more information on this Pokémon's species, see Sharpedo.
Sharpedo (Japanese: サメハダーSamehader) is a Water-type Stage 1 Pokémon card. It is part of the EX Ruby & Sapphire expansion.
Card text
Rough Skin さめはだ
If Sharpedo is your Active Pokémon and is damaged by an opponent's attack (even if Sharpedo is Knocked Out), put 2 damage counters on the Attacking Pokémon.
Dark Slash ダークスラッシュ
40+
You may discard a Energy card attached to Sharpedo. If you do, this attack does 40 damage plus 30 more damage.
Trivia
The Italian-language print says to put only 1 damage counter on the attacking Pokémon when Rough Skin is used. Rulings state to play the Italian card as if it said 2 damage counters, citing "it didn't get weaker as it swam the Atlantic".