Aorth-6

Aorth-6 was a biologically engineered necrotic virus that, once inhaled in gaseous form, liquefied the lungs and spread out to the rest of its victims' bodies to melt them from the inside out. The gas was ineffective against those who possessed artificial respirators in lieu of an organic respiratory system.

During the coup of Headmaster Gentis, his most distinguished cadets—whom he called his "Future Moffs"—released the gas in the Imperial Palace, killing many unsuspecting Imperial officers. Emperor Palpatine himself was infected, but kept his body intact through his connection to the dark side of the Force. Because their respiratory systems were artificial, neither Moff Trachta nor the Sith Lord Darth Vader were affected by the virus when they came to the Emperor's rescue.

Text and facts from the “Aorth-6” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.