Waterfall

Waterfall (, Waterfall Climb) is Squirtle's up special move.

Overview
A torrent of water appears that Squirtle "surfs" on top of. The attack hits multiple times with moderate knockback on the final hitbox. It is difficult to interrupt as a recovery move, as the hitbox is large, disjointed, and directly in front of Squirtle. The movement direction of the attack can be slightly altered with the control stick to either travel straight up with increased vertical distance or at a more horizontal angle with reduced vertical distance in the same manner as Mario's Super Jump Punch.

Origin
Waterfall was introduced in Generation I as the signature move of the evolution line. Starting in Generation II, Waterfall became, being distributed to many Water-type Pokémon, including Squirtle. When used outside of battle, the move allows the player to go up waterfalls. It was made in Generation V and VI. In Generation VII, moves are no longer used outside of battles and HMs were removed as a feature. Waterfall, along with some other former HMs, became TMs instead, making Waterfall in Generation VII. In battle, Waterfall is a physical Water-type attack since Generation IV that has above-average power, and as of Generation IV can make Pokémon flinch 20% of the time.

Squirtle can learn Waterfall via HM07 in Generation II, which allows it to use the move in Generation I via the Time Capsule; it has learned Waterfall ever since as well.