Per 
Item #: SCP-5003
Object Class: Keter
Special Containment Procedures: SCP-5003 is to be contained in an airtight 1” by 1” by 1” steel cube times, in a 10” by 10” by 12” airtight steel cell, with one 3” by 2” observation window, and airlock doors. No ventilation is allowed into or out of the cell at any time without clearance. Surveillance of the cell must be going at all times. No personnel are allowed to enter 5003’s cell, all physical interactions with 5003 must be approved by no less than one third of the O5 Council. Any personnel that gain access must wear a full hazmat suit that has at least one oxygen tank, with the airlocks sealed behind them until they exit the cell.
Description: SCP-5003 appears to be a sentient cloud of a bis(2-chloroethyl)Sulfide substance, a substance more commonly known as ‘Mustard Gas’. SCP-5003 moves on its own accord, and communicate through making itself into shapes, such as; smirks, frowns, checkmarks, etc. SCP-5003 was found in █████, Belgium, hovering above the ground and murmuring near an old trench network. SCP-5003 has a strange greenish, yellow color, that changes depending on its mood. It is extremely impatient and would rather be left alone than have company.
SCP-5003 can move at 40km/h, making it extremely deadly. If SCP-5003 is to breach containment, all ventilation is to be sealed, and personnel are to be given gas masks and/or oxygen tanks. A Class-D is to be retrieved and put inside 5003’s cell without a gas mask, accompanied by two Facility Guards wearing proper hazmat gear, and wielding some form of weapon. Personnel will receive a H.G.G.V (Hazardous Gas Gathering Vacuum) that will be able to recontain 5003 temporarily, and later re-distribute him into his containment.
SCP-5003 is extremely hostile to anything that could be potentially exposed to it’s toxic fumes, and kills its victims by surrounding them in a cloud, and entering their respiratory system, filling up their lungs with toxic fumes and liquid, causing lung scarring, and suffocation. The only way to expel exposure to the gas is by using a gas mask.
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Experiment Log T-39763-DV598/5003
SCP 5003 Capabilities Testing
Due to SCP-5003’s unknown origins, testing has been ordered, with clearance from O5 Command. With major concerns raised about possible hazards and/or breaches, O5 Command has demanded that all tests conducted are to be in airtight chambers, with at least 4 Facility Guards, and 2 Foundation Personnel.
Item: D-4521
Capabilities Test Record:
D-4521 enters 5003’s cell. D-4521 observes the testing chamber, and 5003’s containment cube. A remote control opens the cube, and D-4521 is exposed to SCP-5003. D-4521 gasps, as SCP-5003 enters through D-4521’s nasal and oral cavities. D-4521 is observed falling on the ground, and writhing in the same spot for approximately 2 minutes before all activity ceased. [D-4521: Deceased] Two re-containment units moved into the cell. SCP-5003 was retrieved and contained without incident.
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Audio Logs: None
No attempts to communicate with SCP-5003 have been made.
