A Magikarp living for many years can leap a mountain using Splash. The move remains useless, though.
Magikarp have an easter egg: a «Roasted Magikarp» skin if they have been struck by lightning. The skin is a paler color that implies being «cooked» and has crosses for eyes. If a roasted Magikarp is evolved, the resulting Gyarados will have a special «Zombie Gyarados» skin.