イガク (Igaku) is a VOCALOID track by producer Sasuke Haraguchi featuring the voice of Kasane Teto. The song entered the maimai DX library as part of the PRiSM edition in September 2024, quickly gaining attention for its dense wordplay, medical-themed surrealism, and a high-energy 170 BPM arrangement that bridges Haraguchi's characteristic digital production with Teto's distinctive vocal timbre. The lyrics revolve around a character called "Doctor Kidori" who delivers a stream of absurd, self-referential observations, faces become blunt weapons, legs transform into giant water bugs, and lies become motives, all delivered over a propulsive beat. This combination of nonsense wordplay and medical-examination framing (the title itself is a katakana pun on 医学, "medicine") exemplifies the playful, enigmatic style that defines much of Haraguchi's VOCALOID output. In maimai, イガク is notable for its demanding chart set. The Expert chart, designed by みそかつ侍, features an unusually high concentration of Break notes, 138 out of 520 total, while the Master chart by 鳩ホルダー at level 13+ (constant 13.8) tests players with dense Tap and Hold combinations threaded across intricate Slide patterns totaling 793 notes. The song also crossed over into SEGA's CHUNITHM VERSE in May 2025, where it later received a WORLD'S END chart on April Fools' Day 2026, a fitting nod to its absurdist character.