Yukka

Yukka is a Het ship between Sokka and Yue in the Avatar: The Last Airbender series.

Canon
Sokka first saw Yue when he arrived at the Northern Water Tribe and was immediately smitten by her beauty. The two later had a conversation at dinner that both celebrated Yue's sixteenth birthday and welcomed Sokka and the group as guests. Sokka flirted with her awkwardly, and upon learning that she is a princess, claimed that he was technically a prince from the Southern Water Tribe since he is the son of the chief. Yue enjoyed his presence and giggled at his awkward flirting attempts.

Sokka and Yue later decided to do activities together but the latter eventually ran away crying. When Sokka confronted her, she kissed him but explained that she was engaged. The two decided to still be friends and took a ride on Appa together until they realized that the Fire Nation was coming. Yue complained that she could not just be friends with Sokka who pointed out that she did not even love the man she was engaged to. However, Yue explained that she was doing her duty to her tribe.

Sokka later joined the mission against the Fire Nation and met Yue's fiancee Hahn. Sokka was initially polite to him but was upset when he bragged about the perks of getting married to the princess of the tribe. This prompted Sokka to attack Hahn which got him removed from the mission, as Yue's father wanted him to protect Yue instead. However, the moon spirit Tui was killed so Yue gave up her life as a mortal in order to become the new moon spirit. Sokka objected to this but Yue insisted and kissed him goodbye, saying that she would always be with him. Yue remained in Sokka's heart forever and he had a vision of her in a swamp.

Fanon
Yukka is a very popular ship in the Avatar fandom. Many fans were saddened when Yue died but insisted that she would always be with Sokka in a way. Some fans wrote fan fiction about Sokka being reunited with Yue in the afterlife after he passed away. Sokka's relationship with Yue also started a meme. Sokka once told Zuko about his first girlfriend turning into the moon with Zuko responding with "that's rough buddy" which a lot fans found to be very amusing. Some fan art and photo-shopped screenshots have been made showing affection between Sokka and the moon. Yukka most commonly rivals other Sokka ships such as Sukka although some ship Yukka along with other Sokka ships.