Special Pokémon, commonly known as "Shiny Pokemon" were available to players in PMU 6. They were alternate colorations of Pokémon and were quite hard to find.
Obtaining Shiny Pokémon
Wild Pokémon had a chance of being a different color than usual, resulting in even a common Pokémon such as Ratatta to become desired. However, this addition to the PMU series has been discontinued and is no longer available in PMU 7.