Per 
SCP-079-2 (and SCP-079-3)
chapters
- where dit it came from?
- how to contain and secure it?
- what does it do?
where dit it came from?
It came from scp-079-1.
The story
scp-079-1 did want to open, close and lock doors, so he made an AI (scp-079-2) that would do it for him.
But the AI learned that it should crush everyone (including other scp's) luckely not every time, every third person/scp that walks thru wil be crushed.
how to contain and secure it?
We have 0 information how to kill it we tried do shoot holes in every door chip but that did not work.
We don't know how it works, and it is to much risk removing a door from a wall and placing a new one in.
Even if the parent scp (scp-079-1) is dead or shut down scp-079-2 is STILL WORKING!
So its a Keter. Sometimes the AI tries something new so you just have to pas the door, sadly it can control the 3 closest doors.
what does it do?
As said it crushes every third person that walks thru the door the AI (scp-079-2) is currently controling it can control (but not lock) the 3 closest doors. When it crushes someone it lockes the doors "permanently" (it can only open when the AI decides its time) but the controlled doors (scp-079-3) crushes and opens so you can survive it. The parent AI (scp-079-2) moves when it "stunes" (when he locks the door and later it automatically opens) the door its currently is using (its hp lowers a bit) and it can move to an controlled door (scp-079-3) and the same process can be done to another door (the AI becomes scp-079-2) but the AI can't go back to "stunned" doors (or if they ever where "stunned")
