"A Chilling Discovery" (アイスパレスの戦い Aisu Paresu no Tatakai?, lit. "The Battle of Ice Palace") is fifty-seventh episode of the anime series, Sonic X. It first aired on 15 March 2005 and 8 October 2005 in France and United States respectively.
With the help of Chris' new program, the Blue Typhoon spots a Chaos Emerald on planet Freezy. Followed by Dr. Eggman's Crimson Egg, the Blue Typhoon approaches planet Freezy, but it is attacked by a Metarex robot and it crashes on the planet. Sonic, Chris, Knuckles and Cosmo decide to go get the Chaos Emerald with the X Tornado because Blue Typhoon is damaged. Rouge is also on her way for getting the Emerald before Sonic.
Everybody has to fight the Metarex before reaching an ice palace, where the emerald is supposed to be located. Sonic's group find it, but it's sealed in a solid ice block. A more powerful Metarex appears and gets power from the emerald to become even stronger. A fight engages and Cosmo finds the way to defeat it with a laser beam. The laser from the Blue Typhoon defeats Metarex. The Planet Egg gets trashed into the planet and the snow disappears. Knuckles finds the Chaos Emerald but before he gets it, Rouge steals it. However, Tails discovers that the Emerald was a fake. Rouge soon discovers the Emerald is not real and it crumbles in her hand and she becomes angry.