Nyndra-6 was the name of a top-secret Imperial project, started in 13 ABY 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 New Republic and the gas dissipated into space.