While playing the Pokémon game, you might find a shiny Pokémon. Shiny Pokémon are incredibly rare. When you're surfing, walking in a cave or in a grassy area, and a wild Pokémon appears, there's an extremely slim chance of that Pokémon being shiny. Shiny Pokémon have a different color than normal Pokémon, sparkle when coming into battle and are somewhat stronger.

This is the color difference between a Shiny Chansey and a Normal Chansey:

Other Pokémon don't differ that much from their normal versions, but all of them have the sparkling effect.

The only shiny Pokémon that is easy to find and catch is the Red Gyarados that lives in the Lake of Rage:

Shiny Pokémon can breed with normal Pokémon, but can't breed with other shiny Pokémon. If you try to do it, you'll get the "Brimming with energy" message. Click here for more info on breeding.