「『ウソテイ』 ～一回戦せりなvsしろなvsなずな～」 (Uso Tei ~First Round: Serina vs Shirona vs Nazuna~) is a crossover track from SEGA's CHUNITHM series, performed by the in-game fictional band Irodorimidori (イロドリミドリ). The subtitle names three of the band's members, Serina, Shirona, and Nazuna, squaring off in a theatrical "first round" battle, giving the song a playful, competitive energy befitting its origin as a CHUNITHM character song. The title is a deliberate pun on ウサテイ (Usatei), a well-known Touhou Project arrangement by Amane + Beat Mario (COOL&CREATE) that medleys two classic themes: "O Usa-sama no Soi Hata" from Touhou Kaeizuka and "Cinderella Cage ~ Kagome-Kagome" from Touhou Eiyashou. By swapping ウサ (usa, as in usagi/rabbit) for ウソ (uso, lie/false), the name announces itself as a cheeky, "fake" twist on the original, a fitting gesture for a song built around character rivalry and playful one-upmanship. Added to maimai DX as part of the FESTiVAL PLUS update on June 8, 2023, the track charges ahead at 190 BPM. Its Master chart (Lv 13+, constant 13.7) was designed by サファ太 (Safata), while the Expert chart (Lv 10) was laid out by はっぴー (Happy). Players who achieve S rank on Expert earn the title わるのりみどり (Waru Nori Midori).