Visit a participating Toys R Us in the United States or Puerto Rico from March 8th through March 21st to receive the Colossal Pokemon Regigigas in your copy of Pokemon Diamond Version or Pokemon Pearl Version.
Poke Ball: Cherish Ball
Held Item: Custap Berry
Moves: Iron Head, Rock Slide, Icy Wind, Crush Grip
If you receive this Regigigias and then transfer it to your copy of Pokemon Platinum Version, something amazing happens! If you have Regigigas in your party at certain times, you may be able to find Regirock, Regice and Registeel in Sinnoh. Once you encounter them, you'll be able to catch these Legendary Pokemon.
This trio of Legendary Pokemon cannot be found in Pokemon Platinum Version during normal play and a Regigigas caught through normal play in Pokemon Platinum Version will not cause these Pokemon to appear.