Chaos/Miscellaneous

Archie Comics
The Sonic the Hedgehog comic series echoed the Sonic Adventure storyline, with a number of variations. Chaos and Tikal were both imprisoned in a Black Emerald, which was broken open by a hammer wielded by Dr. Robotnik. This continuity also featured the Freedom Fighters, who assisted Sonic and Knuckles in the victory over Perfect Chaos. Chaos was later featured in the Worlds Collide crossover, the events of which led to an altered continuity in which the events of Sonic Adventure apparently occurred in the comic universe in exactly the same way as in the game.

Sonic X
The Sonic X anime follows the plot line of Sonic Adventure in episodes 27-32, resulting in Chaos's presence in those episodes in several of his forms. Here, he is described as "energy in a liquid state" rather than the "God of Destruction" in the English dub of the anime. He also made a few appearances in the Sonic X comic series published by Archie Comics.

Reception
Despite the fact that its main appearances were in three main series games, Chaos has become one of the most popular Sonic characters and has ranked as ninth in an official poll, sitting between Metal Sonic in eighth place and Rouge in tenth.

Theme songs
Chaos has a number of theme songs in the games that are attributed to itself. The genres of the songs vary.
 * "Boss: Chaos ver.0, ver.2; ver.4" - plays during the battles against Chaos 0, 2 and 4. It is also used in Super Sonic's story summaries as there is an image of Perfect Chaos in the backdrop.
 * "Boss: Chaos ver.6" - plays during the battles against Chaos 6.
 * "Perfect Chaos Revival" - plays during the second half of the battle against Perfect Chaos. It also plays in Mario & Sonic at the Olympic Winter Games when Perfect Chaos appears.
 * "Open Your Heart" by Crush 40 - plays during the first half of the battle against Perfect Chaos; shared as the main theme of Sonic Adventure. A cut-down, instrumental version is also used in Mario & Sonic at the Olympic Winter Games.
 * A special song plays in the fight against Chaos 0 during the Story Mode of Sonic Battle. It has no name, but is number 18 in the Sound Test.

Trivia

 * In Greek mythology, Chaos was the name of the first deity to come into existence. It is described as vast and formless, much like the being from the Sonic series. According to Hesiod, Chaos was also the dark void from which the Earth goddess Gaia was born.
 * Although Chaos first appeared in Sonic Adventure, he was briefly alluded to as early as the prologue in the manual for the Japanese version of Sonic the Hedgehog 3, where Knuckles speculated that the crashed Death Egg in the lake on Angel Island was the egg containing a legendary dragon that was fated to destroy the world.
 * Because of positioning on the map, Big the Cat is able to come in contact with Chaos 4 prior to his battle with Chaos 6 by approaching the arena from the proper direction and jumping into it. This is the only time that directly touching Chaos does not harm a character.
 * In Sonic Adventure and Sonic Generations, Chaos is translucent, but in all his other appearances he is opaque.
 * Chaos 1 is the only seen form of Chaos not to have a boss.
 * Chaos 1, 2, 4, and 6 have what appear to be bones, but Perfect Chaos does not have any. The bones are probably meant to hold the Chaos Emeralds in place until he has all seven of them.
 * Chaos 3 and 5 are never seen, as Eggman gives Chaos the third and fourth emerald at the same time and he gives the fifth and sixth emerald to him off-screen.
 * When the Chaos Emeralds are in Chaos, they look like a gradient color tint rather than their usual diamond design. Additionally, the emeralds that appear inside Chaos are rarely the same color as the actual Emeralds he has received; his second Chaos Emerald, the Gray Emerald, appeared Red once he had absorbed it.
 * Chaos was purposefully created for Sonic Adventure to be a boss that would have been difficult to render on systems before the Dreamcast.
 * In Sonic Adventure 2, Chaos is featured on several billboards. First, billboards advertising two fictional soft drinks (Chaos Cola and Chaos Soda) appear in several stages, such as Shadow's Radical Highway stage. Second, in City Escape and the Big Foot boss battle, Chaos 0 can be seen on billboards advertising a fictional movie named Planet of the Chaos, apparently based on Planet of the Apes. The movie is shown to be rated PG-13 by the MPAA.
 * There is a special kind of Chao, called the Chaos Chao, whose head and limbs resemble those of Chaos 0.
 * Chaos and Chaos Gamma are the only playable characters in Sonic Battle that do not have a story mode.
 * They are also the only unlockable playable characters in Sonic Battle.
 * Chaos was intended to be in Sonic Heroes in a team with E-102 Gamma and Big. This is likely why Chaos and Gamma appeared in Sonic Battle instead of Omega or the Chaotix.
 * According to an interview on Sonic Central, Sonic does not know the whereabouts of Chaos, Fang the Sniper, Bark the Polar Bear, Ray the Flying Squirrel, Bean the Dynamite, or Tikal.
 * Chaos appears as the final boss in the Sonic the Hedgehog Level Pack of LEGO Dimensions. In this game, a giant Chaos 0 from another dimension attacked the Death Egg seeking the Chaos Emeralds, where it fought Sonic the Hedgehog until Sonic could go Super Sonic and defeat the beast.