ジェットブラック (Jet Black) is a niconico & VOCALOID song by producer Yunosuke (雄之助), featuring vocals by Hatsune Miku. Released for maimai DX CiRCLE on November 20, 2025, it was created as the third installment of Project ONSOKU, a cross-promotional collaboration between Sonic the Hedgehog and Hatsune Miku that spans multiple Sega rhythm games including CHUNITHM X-VERSE and ONGEKI Re:Fresh. The lyrics were written by Gyuuniku, and the music video was produced by the creative unit Cube / FAMY. The song's title and chorus reference "Jet Black", a color that the lyrics weave into imagery of darkness, determined pursuit, and unwavering will. Its aggressive electronic production and driving 170 BPM tempo are hallmarks of Yunosuke's style, blending tight synth work with Miku's signature vocal synthesis. In-game, the MASTER chart (designed by じゃこレモン) carries a level constant of 13.2, while the EXPERT chart (designed by はっぴー) sits at level 10. A notable in-game achievement, the "カオスコントロール!" (Chaos Control) title, directly references Shadow the Hedgehog's signature ability from the Sonic series, a deliberate nod to the Project ONSOKU collaboration that birthed the track.