Sogebu

SoGeBu (そげぶ) is a Japanese meme that revolves around the abbreviation Kamijou Touma's signature line "Sono Gensou wo Buchikorosu" (その幻想をぶち殺す) translated as "I'll break that illusion of yours." Either an Shift_JIS art figure that takes four poses or an image of a character is used while reciting the line, despite the fact that Touma has never made such a pose when reciting the line.

Sites such as Pixiv host artwork and even an encylopediac definition of the meme.

Shift_JIS art
The pose is often accompanied by Shift_JIS art. The Shift_JIS art most likely originated and used in 2ch textboard though this is unconfirmed. ヘ(^o^)ヘ いいぜ ∧ 　　　　　　　　　　　　　　　　　　　　　　／　　/　　　　　　　　　　　　　　　　 (^o^)／ てめえが何でも ／( 　)　　　 思い通りに出来るってなら (^o^) 三　　／　／ ＞ ＼　　　　 (＼＼ 三　(／o^)　　＜　＼ 三　　( ／ ／ く 　まずはそのふざけた 幻想をぶち殺す

References in the Toaru Majutsu no Index franchise
The meme was referenced in the 4th episode of Toaru Majutsu no Index-tan in the final sketch of the episode, where Index-tan rides Touma's head and after being angry with him proceeds to make him bald by picking on his hair, saying Sogebu afterwards.

Finally, a subtle reference to the meme is featured in the 5th Shinyaku Toaru Majutsu no Index light novel. Here, Touma confuses Misaka Mikoto for Thor, whom had disguised himself as Mikoto before, and after mocking her breast size says "Genkoro" (ゲンコロ), an abbreviation of his famous line (translated as IDTI in the Baka-Tsuki release).