This Mistake Changed Pokemon Forever
Poor Magikarp. Long considered the most useless of Pokemon, this fish-like Pocket Monster from Generation 1 is well known for being able to do nothing but flop around. In battle, you basically level Magikarp up by letting it take damage for a few rounds and gain experience before switching to a more powerful and helpful Pokemon.
Despite that, Magikarp is well-loved — so much so it even got its own mobile game in Japan. Maybe this is because it is so helpless at first, yet eventually becomes the much more effective and kick-butt Gyarados. It's your basic ugly duckling story. GamesRadar+ noted that "Magikarp is the unlikely mascot for delayed gratification, offering 20 levels of tedium before its jackpot. It's a reflection of the child-focused world of Pokemon that no critter could ever be a total waste of time, and that effort and investment are always acknowledged."
As fans know, Magikarp's signature move is Splash, which doesn't actually do anything. When the "attack" is used in most games, players receive this message: "The user just flops and splashes around to no effect at all..." Yet somehow, the Splash move has influenced the Pokemon community and gameplay for years — a legacy you can trace back to a single translation error.
Non-Water-type Pokemon learn to Splash
Don't think that somewhere along the line, Splash became a useful move. No, it has remained pretty consistently useless throughout all the generations of Pokemon games. However, starting in Pokemon Sun and Moon, you could upgrade it to a Z-Splash move that raised your attack stat by three stages.
For some reason, somewhere around Pokemon Gold and Silver, Splash became a move that could be utilized by non-Water-type Pokemon. Magikarp could wield the power at any level — but others, like Hoppip, a Grass/Flying-type Pokemon, gained the power starting at level 2. Pokemon like Clefairy (Fairy-type), Grumpig (Psychic-type), Mimikyu (Ghost/Fairy-type), and Buneary (Normal-type) also developed the useless Splash power at different levels. Other Pokemon can even obtain Splash by breeding and through events.
In all Pokemon, Splash manifests as hopping up and down a few times, which about as exciting as it sounds. This brings up an important question though: how (or why) can Pokemon Splash without water?
Splash appears to be the result of an early mistranslation
As it turns out, the word used for the Splash attack was reportedly mistranslated in the first Pokemon games, Red and Blue. According to Bulbapedia, the Japanese name is actually "Hop." This makes sense, since most of the Pokemon that use Splash look like they're jumping.
When Red and Blue were translated for English-speaking audiences, Splash was possibly chosen because it matched Magikarp's Water-type abilities better. Since it doesn't have legs, Magikarp doesn't hop so much as wiggle around. It makes sense, in that respect. Whomever was responsible for giving the move that name was possibly not thinking far enough ahead to realize that other Pokemon would be using the same attack later on. The moniker "Splash" would definitely make less sense when applied to Grass-type and other Pokemon.
As time passed, Splash stuck around. And now, it's pretty much accepted that, although there may not be any water in the vicinity, the move is here to stay in the Pokemon series. Way to create a lasting (if odd) legacy, Magikarp!