Use any attack from Kingdra ex's Basic Pokémon card or Stage 1 Evolution card. (Kingdra ex doesn't have to pay for that attack's Energy cost.)
Does 50 damage plus 20 more damage for each Energy attached to Kingdra ex but not used to pay for this attack's Energy cost. You can't add more than 40 damage in this way.
This card's Genetic Memory attack comes from the attack of the same name possessed by Neo RevelationKingdra. Aside from having different Energy costs, the attacks function identically.
Hydro Cannon, formatted on this card as Hydrocannon, is a move in the Pokémon games, though Kingdra cannot learn it. The Japanese name of Hydro Cannon is spelled ハイドロキャノン rather than ハイドロカノン as in the video games.