Kumo no Ito (蜘蛛の糸) is a collaborative composition between two towering figures of the doujin music scene, Kikuo (きくお), widely known for his dark, surreal electronic soundscapes, and cosMo@BousouP (cosMo＠暴走P), synonymous with blistering vocaloid boss tracks such as The Disappearance of Hatsune Miku. Featuring vocalist Kagenui (影縫英), the track unfolds at a driving 180 BPM, weaving together Kikuo's eerie melodic sensibility with cosMo's signature manic energy. The song's title and lyrical theme draw from Ryunosuke Akutagawa's classic 1918 short story "Kumo no Ito" (The Spider's Thread), in which a single thread is lowered from paradise to hell. The MASTER chart brings this motif to life visually, with touch notes arranged in a web-like formation during the intro. Kumo no Ito was originally introduced in SEGA's CHUNITHM NEW and later ported to maimai DX as part of the Geki! Chuu Mai cross-title initiative, meaning it appears in all three SEGA rhythm game series, maimai, CHUNITHM, and Ongeki. Its arrival in maimai DX FESTiVAL on September 15, 2022 sparked discussion among the playerbase due to an unusual unlock situation: at the time of the maimai port, the song had not yet received a general unlock in CHUNITHM. This made it the first cross-title collaboration song to require unlocking on the source side first, with conditions that effectively demanded completion of CHUNITHM NEW ep.I - Side.B. A CHUNITHM version update on October 13, 2022 normalized the requirements to the standard cross-title play condition. The jacket illustration, drawn by Ohisashiburi (お久しぶり), features the CHUNITHM character Kozakata Toa (不来方 とあ) at center.