Water Spout deals damage, with its power reduced the lower the user's HP. In the Rescue Team and Explorers series, the final damage is multiplied by ½ when at 75-51% HP, 51/256 (~0.2x) when at 50-26% and 25/256 (~0.1x) when at 25% or lower. In Super Mystery Dungeon, the power reduces proportionally to the user's HP. When used by a gigantic Pokémon in Super Mystery Dungeon, Eruption hits all enemies in the room.
In Pokémon UNITE, Water Spout is Blastoise's first move. It is obtained by evolving into Wartortle stage at level 5 and upgrading Water Gun into it instead of Hydro Pump. The user calls down a barrage of water in a targeted radius. Enemies within the radius are struck 6 times over its duration, damaging and slowing them. At level 11, its damage increases.
This article has information requiring translation. If you are able to translate Japanese and would like to help, please add the English translation to the section or sections in Japanese.