Giko Neko (ギコ猫, lit. “Giko Cat”), also known as Giko (ギコ) and Giko Hanyan (ギコ・ハニャーン), is an AA character that had started out on Ayashii World in December 1998, then ended up on 2channel in 2000, and completely changed into the “Giko Neko” that we know today.

 　　　 　∧ ∧
 ～′￣(´ー`)
 　UU￣ U  U

Around December 3, 1998, the Ayashii World users made 'Giko Neko' (擬古猫), who was initially named after the 'gikogiko' (ギコギコ) sound¹⁾ and the 'gikohahaha' (ギコハハハ) laugh, but kanji misconversation led to it being rendered as 'giko' (擬古, lit. “imitating a classic”) instead. In turn, the cat's personality mostly consisted of using classical expressions with a slight modernistic twist to it.

　　＿＿＿_∧∧
～'　＿＿__(,,ﾟДﾟ)
　 ＵU 　 　Ｕ U

At some point, he was picked up by 2channel around 2000 and became 'Giko Neko' (ギコ猫) where he was given a new face, longer body, and started being used in a versatile manner as this variant spread.

• Gorya! (ゴルァ！) - A variantion of 'kora' (こら！), which is something that people would shout to get somebody's attention or reprimand someone, depending on the context.
• Hanyan (ハニャーン) - Giko's catchphrase and surname. It actually came from Cardcaptor Sakura, where it was originally used as Sakura Kinomoto's catchphrase.
• Itteyoshi! (逝ってよし！, lit. “you can die” or “ready to die”) - An old workaround for 'die' (死ね, shine) from a time when it was wordfiltered in the 1990s. It actually comes from The Prince of Tennis, where the Hyōtei Tennis Club coach Tarō Sasaki says 'itteyoshi' (行ってよし, lit, “you can go”).

• Mona, Shii, and Morala - The other three members from the original big four of 2ch AA.

• Giko on the 2ch AA Illustration Project
• Giko on Pixiv Encyclopedia
• Giko on Niconico Encyclopedia