PUPA is a high-energy instrumental track by doujin and BMS composer Morimori Atsushi (モリモリあつし), built around a relentless 202 BPM drive. The song first emerged from the GO BACK 2 YOUR ROOTS, THE BMS OF FIGHTERS 2004 RELOADED, competition, where it placed 22nd under the genre label "HARD RENAISSANCE." Its title refers to the pupal stage of butterfly metamorphosis, and over the years the track's melodic intensity has made it one of the most widely ported songs in the rhythm game scene, appearing in over a dozen titles including Arcaea, SOUND VOLTEX, Muse Dash, DJMAX RESPECT V, and CHUNITHM. In maimai, PUPA joined the でらっくす BUDDiES lineup at the edition's launch in September 2023, available across Japan, Asia, North America, and China. The MASTER chart, designed by じゃこレモン (Jako Lemon) at level 14 (constant 14.4), is a dense high-speed marathon of 964 notes that demands consistent accuracy across all five note types. The EXPERT chart by 鳩ホルダー (Hato Holder) at level 12+ (12.8) prepares players with a 666-note gauntlet of its own. The track forms a thematic insect-metamorphosis pair with its sequel larva, also present in the maimai series, and both songs share unlockable title bonuses when played together in a single credit.