Per 
SCP-4757
Object Class; Apollyon
description:
SCP-4757 Is a Large cloud of unknown Gas that stays no more then 5 meters off the ground. SCP-4757 is highly radioactive and extremely dangerous, for what ever enters SCP-4757's cloud of gas, immediately Starts to rapidly corrode and rot until there is nothing left of the material. Anything that corrodes inside SCP-4757 turns into more of SCP-4757's gas and becomes part of the mass. Chemicals, other gases, Animals, buildings, plants, dust and other materials are vulnerable to SCP-4757 but water Seems to not react to this, making water a possible form of containment. Attempts to get samples of SCP-4757 have all failed and have resulted in the deaths of five personnel. Any testing regarding SCP-4757 have ceased. the interesting part of SCP-4757 is that it appears to have a high awareness of its surroundings, Even being able to track down Other things to turn into more of its gas. SCP-4757 was found at the Semipalatinsk test site in [REDACTED] When there was reports of "A large cloud of Killer gas" Sweeping through the area turning everything into more SCP-4757 gas. SCP-4757 is able to travel at a speed of [REDACTED] meters a second, making escaping from SCP-4757 a loss cause.
special containment procedures:
Due to the nature of SCP-4757 containment is currently Impossible, Although multiple surveillance and MTF personnel have been placed around the area of containment. Any entry into SCP-4757 is prohibited, and whatever tries to enter SCP-4757's containment area is to be immediately terminated and removed from the area of containment to prevent SCP-4757 from gathering more mass. Any personnel trying to enter SCP-4757 is considered expandable and is to be immediately terminated and removed from the area. SCP-4757 is to be monitored at all times, any change in SCP-4757 is to be immediately informed to the administer. If SCP-4757 were to gain enough mass, it could mean an end of the world situation Resulting in the extinction of all life on earth. If SCP-4757 were to gain even more mass, It could travel to other planets or even other systems entirely. If a breach were to happen, all personnel are to evacuate the area and into the nearest underground shelters until further instructions.
