Utilizing high-tech nano-scale photo-absorbent particulates, While it appears like a smoke grenade on deployment, moments later the nano-particulates in the free air attract to one another, creating a bubble held together by the surface tension of the dispersed motes.
In effect, this grenade creates a dome of darkness, necessitating the use of night vision, thermal optics, or some portable light source.
(It's a grenade that casts 'darkness'. I think it would be a neat addition to the game.)
