A frenetic, high-BPM Vocaloid romp from producer 南ノ南 (Minamino Minami), 星界ちゃんと可不ちゃんのおつかい合騒曲 (Seika-chan to Kafu-chan no Otsukai Gassōkyoku) brings together two of KAMITSUBAKI STUDIO's virtual singers, 星界 (Seika) and 可不 (Kafu), for an errand-themed musical free-for-all. The title itself is a pun: 合騒曲 (gassōkyoku) replaces the 奏 (performance) of "ensemble piece" (合奏曲) with 騒 (commotion), painting the track as a deliberately chaotic ensemble rather than a polished one. Clocking in at 220 BPM, the song sustains an unrelenting energy that matches its mischievous premise. Added to maimai でらっくす BUDDiES on October 6, 2023, the song lives in the niconico & Vocaloid category and is available across all regions (JP, International, USA, CN). Its Master chart (Lv13+, constant 13.8), laid out by はっぴー (Happy), packs 1,045 notes with a notably high Slide-note count of 224, a signature density that keeps the playfield in constant motion. The Expert chart (Lv11+, constant 11.6) was built by Luxizhel, and the lower Basic and Advanced difficulties have no credited designer. A post-release 宴 (banquet/party) chart arrived on August 22, 2025, designed by the aptly named せかせかせかせかせかせかせかせかせかせか (whose handle evokes a frantic, snappy rhythm). This 宴 chart, estimated at level 14, balloons to 1,297 notes and serves as a endurance-focused alternative layout for players seeking a different kind of challenge. In-game, players can earn the title "正しいのは私" (I am right) by winning a matching-play session with this song selected.