In Japan, the move splash is actually called hop, which is what it really is interpreted to be because there is no water splashes in the animation at all. Only Magikarp, Hoppip, Spoink, and Buneary can learn this move. Gamers who played the game were confused about it because it is not a water-type move, it is actually a normal type move. It is known has the most weakest move in the entire Pokemon game series, it became famous from the weakest Pokemon, Magikarp. 

You have to catch a Magikarp though. Why, because it evolves into the most voilent and powerful water type Gyarados. It is known as the atrocious Pokemon. It has a feirce temper and is very voilent, it will not calm down until everything around it is destroyed.