Allows players to climb waterfalls. Note that in Generations II and III, the HM move Waterfall is not required to go down waterfalls, whereas in Diamond, Pearl, and Platinum versions, it is required. This is probably to prevent players from getting stuck from accidentally going down a waterfall and being unable to get back up. Despite this, in HeartGold and Soulsilver versions, it is no longer required to go down waterfalls, likely because of a lack of accessible down falls without first climbing up one.
In Super Smash Bros. Brawl, Waterfall is Squirtle's Special Up move. It can be used by Squirtle as a recovery move and offers high knockback at the very end of the move.
Goldeen releases a stream of water at the opponent from its mouth. The water can stay in the air long enough for Goldeen to swim across the top of it as well.