Per 
Item #: SCP-4086
Object Class: Euclid
Special Containment Procedures: SCP-4086 is kept in a 3m x 3m x 3m cell made of 5" thick lead, 0.4 km below sea level, the chamber is airtight with no air or other gases entering the cell. The only entrance to the cell is through an airlock chamber. Oxygen masks must be worn at all times when in the presence of SCP-4086.
Description: SCP-4086 is an invisible cloud of an unknown gas, it appears to have a mind of it's own and is extremely hostile. It can take control of other gases when it comes in contact with it, turning it into itself and expanding. If any Foundation Staff becomes infected with SCP-4086 protocol █████ is to be executed and the infected victim is to be placed in quarantine. SCP-4086 can infect by Humans/Animals inhaling it. The effects of SCP-4086 will kill anyone that is infected within 5 minutes. When infected the lungs clot up with blood, suffocating the victim, the esophagus begins to swell and tear, the veins clot leading to death.
Addendum:
The following test was conducted by Doctor █████
** TEST SUBJECT:**
D-8365 - Caucasian Female
[BEGIN LOG]
Dr. █████:D-8365, please step into the chamber.
D-8365: There's nothin' in here doc.
Dr. █████: D-8365, step into the chamber or you will be neutralised.
[D-8365 Enters Chamber]
D-8365: Nothin' in here, like I said.
Dr. █████: Do you feel anything?
D-8365: No
Dr. █████: Proceed back to the door.
[D-8365 Stops]
Dr. █████: D-8365, why have you stopped?D-8365: [Inaudible]
Dr. █████: D-8365, what is wrong?
D-8365: Doc.. [Inaudible] I ca-
[D-8365 Collapses, Choking]
[Audio Detected]
SCP-4086: LET US FREE
[Video Offline]
[END LOG]
// was announced dead immediately after retrieval//
