Greninja uses water to propel itself upward, in a manner similar to Pikachu's Quick Attack in that it can change directions while it moves. However, unlike Quick Attack, the move can move twice the distance in a single direction, is a little slower, and carries most of the momentum gained, which gives it better maneuverability than Quick Attack does. Hydro Pump also deals slight damage with decent knockback and does not cause flinching, which can be used to gimp. While it offers excellent distance, Greninja will immediately start falling once the second water stream ends, which can often cause inexperienced players to underestimate the vertical distance gained from this move. It will also cancel if Greninja bumps into a wall, sending it into a tumble. If this happens, Greninja will no longer be able to use jumps or Shadow Sneak, or reattempt another Hydro Pump until cancelled by landing or with an aerial, Water Shuriken, or Substitute. Greninja is still capable of wall clinging, and thus wall jumping, and is its only means of recovery in this scenario (though Substitute grants mobility if successful). Unlike typical tumbling, Greninja does not need to tech in order to prevent crash landing, and can act immediately as though they had fallen normally.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
Use by other Pokémon
Hydro Pump is a powerful special Water-type move with 110 base power but has 80% accuracy that was introduced in Generation I and was considered the strongest Water-type move before Generation III.
Greninja like other Water-type starters is capable of learning this move by leveling up. Hydro Pump is described as "blasting the foe with huge volume of water launched under great pressure" and is usually depicted as a single, large torrent of water launched at the foe, contrary to Greninja's usage in SSB4 which involves riding two thin jets of water in the style of the Smash version of Quick Attack (which has a Pokémon series Water-type variation known as Aqua Jet which Greninja can't learn).
Names in other languages