Red Gyarados (あかいギャラドス) is the shiny version of the Water/Flying-type Pokémon Gyarados, which is red instead of its normal blue color. It first appeared in Pokémon Gold and Silver, where it is located at the Lake of Rage. Due to the radio waves transmitted from Team Rocket's hideout, it became irritable and started to tip over boats and scare off swimmers of the lake.
Red Gyarados, just like a regular Gyarados, is a vicious and destructive Pokémon that lives in the bodies of water. Its violent nature is possibly caused because of a change in its brain cells due to the evolution; this is why it is feared by many. Its fangs can crush stones and its scales are harder than steel. At times, it may appear and causes destruction across the surrounding area.
In the Pokémon anime, Red Gyarados prominently appears in the episodes "Talkin' 'Bout an Evolution" and "Rage of Innocence", where it is revealed that it was a regular Magikarp that went under a forced evolution, which resulted in its skin staying red instead of turning blue because it did not have time to officially complete the evolution.