Chaoikal

Chaoikal is the non-binary ship between Chaos and Tikal from the Sonic the Hedgehog fandom.

Sonic Adventure
Tikal discovered the Chao near the Altar of Emeralds. While Tikal's presence frightened the Chao at first, she quickly earned their trust. This got the guardian of the Chao, Chaos, to reveal itself. Tikal was, at first, frightened by the water creature, but quickly learned its gentle nature. Tikal and Chaos became good friends, and Tikal would spend most of her time near the Altar of the Emeralds. Eventually, Chaos decided to let Tikal enter the inner altar, where she saw the Chaos Emeralds and the Master Emerald.

Tikal's tribe, lead by her father, Pachacamac, decided to take the Chaos Emeralds to use them against the tribe's enemies. Tikal opposed this, but Pachacamac did not care. Tikal returned to the altar to warn Chaos and the Chao about the attack and told them to get to safety, but they could not leave. Tikal then tried to convince her father not to attack the altar again, but it failed, and Pachacamac lead his clan there. Tikal blocked the path and refused to move. She tried to convince the clan that greed was their true enemy, but they did not care, and the clan trampled over her to attack the altar.

The attack of Pachacamac and his clan angered Chaos to the point where it got corrupted by the negative energy of the Chaos Emeralds. Using this energy, he transformed into Perfect Chaos and killed most of the Knuckles Clan in anger. Seeing as Chaos only wanted destruction due to the negative energy's corruption, Tikal sealed both herself and Chaos inside the Master Emerald, where they would remain for millennia.

Over 4000 years later, Chaos and Tikal were released from the Master Emerald by Dr. Eggman, who attempted to use Chaos for his plan to take over the world. While Eggman was collecting Chaos Emeralds to feed Chaos, Tikal, in spirit form, found heroes to whom she showed parts of her past in order to warn then of the consequences of Chaos gaining the powers of the seven Chaos Emeralds.

Despite Tikal's attempts, Chaos became Perfect Chaos again and began destroying Station Square. Perfect Chaos betrayed Eggman and destroyed his Egg Carrier. Tikal showed up in front of Sonic in her physical form, and told Sonic about Chaos' emotions and that Chaos would have to be sealed in the Master Emerald again to prevent destruction. Sonic, however, refused, as this would just keep Chaos trapped without his anger ever vanishing. Sonic used the positive energy of the Emeralds to turn into Super Sonic. He defeated Chaos and neutralized the energy in the process, turning it back into its normal form. Tikal showed Chaos that the Chao were still okay, and the two disappeared in a flash of light. Their whereabouts are unknown, but it is presumed the two continued to watch over Chao.

Other appearances
Tikal and Chaos appeared as playable characters in the multiplayer mode of Sonic Adventure 2. The two were treasure hunting type characters alongside Knuckles the Echidna and Rouge the Bat.

The two have made cameo appearances in multiple games.

In Sonic X and both the Pre- and Post-Super Genesis Wave Archie Comics, Tikal and Chaos have roughly the same story as in Sonic Adventure, with some changes to fit into the narratives of their respective universes.

In the Light Mobius timeline, Tikal and Chaos merged into one being known as Tikhaos. In its normal form, it had the shape of Tikal and the water-like appearance of Chaos. It had a hunger for Chaos energy, but when given too much, it would transform into the unstable Perfect Tikhaos. This transformation was used by Lien-Da and King Shadow. Tikhaos was reverted back to its normal form by the Future Freedom Fighters.

In Sonic the Comic, their story is more different. Chaos was originally a member of the Drakon Empire. As Chaos was attacking, Tikal knew it was a beginning of a great war. Tikal also saved Sonic from almost getting killed by Chaos by summoning her father, Pochacamac.

Fanon
Chaos and Tikal are generally not shipped romantically, although the pairing does have a decent amount of fanart on DeviantArt. It is rarely referred to by its ship name. It is among the most popular ships, if not the most popular ship, for Chaos as Chaos is generally rare in shipping. For Tikal, it is notably less popular than major ship Knuxikal.

Fandom
DEVIANTART

Trivia

 * It is a non-binary ship due to Chaos being genderless, but can also be seen as het as Chaos is often referred to as male.