Nova Gas

Nova Gas is a special grenade that is scheduled to appear in Call of Duty: Black Ops.

Description; "Start with two gas grenades that impair movement, blur vision, and cause damage over time." makes it very likely that it acts like Tabun Gas or Stun Grenade with a damaging effect. If you stand in the gas for at least 5 seconds in full health, you die, and much like a Tabun Gas Grenade it slows you down, making it an extremely deadly special grenade. Damage with the Tactical Mask Perk is still unknown.

Trivia

 * "Nova Gas" is also the name of a chain of fuel stations in Modern Warfare 2.
 * Nova-6 might be the gas emitted from the grenades.