Sleeping Gas or more precisely, Fentanyl is a weapon seen briefly in Underworld: Awakening. It is likely that sleeping gas is used in the rooms of all Antigen subjects in case the subject should break free and/or harm an Antigen employee.
Fentanyl was used when Selene awakens from her Cryogenic Chamber. On orders of Jacob Lane, director of Antigen, Alan releases this gas to put Selene to sleep, but she flees her room into the observation room before the gas can take effect. The gas is used later in Eve's chamber, with the intention of putting her to sleep so she can be vivisected.
|Selene - Eve - David - Jacob Lane - Quint Lane|
|Thomas - Lida - Alan - Michael Corvin - Detective Sebastian - Olivia - Edward Vronski - Officer Kolb - Corvinus Clan|
|Vampire - Lycan - Hybrid - Immortal - Human|
|Weaponry of Underworld: Awakening - Swords - Sleeping Gas - Silver Nitrate Bomb - Beretta 92FS - Whips - Shurikens - Silver - Silver Bullets|
|Antigen Headquarters - Thomas's Coven - Cryogenic Chamber - Army Surplus Store - Pier 9 - Abandoned Building|
|Corvinus Strain - Death Dealer - Vampire Elder - Blood Memories - The Purges - Antigen - Infected Persons Unit - Vampire-Lycan War|
|Music - Quotes - Images - Soundtrack - Score|