にっこり^^調査隊のテーマ (Niccori^^ Survey Team Theme) is a high-energy Vocaloid track born from the Project Sekai: Colorful Stage! feat. Hatsune Miku ecosystem, composed by the prolific circle Wonderful☆Opportunity! (ワンダフル☆オポチュニティ！). The song serves as a signature piece for the in-game unit Wonderlands×Showtime, a troupe of theatrical performers whose bright, over-the-top stage presence matches the track's relentless cheerfulness. The title's ^^ glyphs form a smiling face, reflecting the song's theme of a jovial investigation team setting out on an adventure. The track was added to maimai でらっくす BUDDiES on January 11, 2024 under the niconico & Vocaloid genre, continuing the series' ongoing collaboration with Project Sekai. At a steady 180 BPM, the song's instrumentation is driven by brisk synth leads, punchy percussion, and playful vocal delivery, characteristics that carry directly into the chart design. Two official music videos exist: the original MV featuring Kagamine Rin and Len produced by Wonderful☆Opportunity! themselves, and a 3DMV version starring Hatsune Miku alongside the Wonderlands×Showtime cast complete with choreography. In the maimai arcade, the song is represented across four DX difficulties. The MASTER chart (level 12+, constant 12.7) was crafted by はっぴー and contains 709 notes, with generous Slide (109) and Touch (67) placements that mirror the song's bouncy, theatrical phrasing. The EXPERT chart (level 10) was designed by サファ太 and features 488 notes anchored by 50 Break notes, giving intermediate players a taste of the song's rhythmic energy. The chart is available across all maimai regions, Japan, International, USA, and China.