Nyndra-6

Nyndra-6 was the name of a top-secret project, started in 5 BBY the aim of which was to create a gas that would kill those who inhaled it in a matter of nanoseconds. After years of trial and error, the project finally saw success in 19 ABY but before the Imperials had a chance to use their deadly new weapon, the Star Destroyer carrying the only completed shipment was destroyed by a fleet of the and the gas disapated into space.

Behind the Scenes
Nyndra-6 is based on "Nova-6", a gaseous bioweapon featured in the recently released Call of Duty: Black Ops.