A TLDR won’t do them justice, but I can keep it short.
SCP stands for “Secure, Contain, Protect”.
The SCP Foundation lives by this principle. They secure and contain paranormal objects, and protect the whole of humanity from them. They are a massive international organization, with access to practically unlimited resources, manpower and co-operation from Governments. They have the power to cause media blackouts, kill or relocate people if necessary, clear entire areas of people for the sake of containing SCPs, etc. They also have access to what are called “Amnestics” or “Amnesiacs” which they use to make people forget things (much cleaner than executing someone).
SCP is also a term that refers to the paranormal objects. Each object is given a serial number, a safety class, some tags, and most importantly special procedures on how to contain the object, or at the very least minimize injuries to the general public. The only thing that all SCPs have in common is that they have paranormal qualities.
The SCP Foundation is also ruthless and amoral as you can be without being evil. They’ve done some pretty horrible things for the sake of the greater good of humanity.
The closest thing you could have to an SCP in Cataclysm is the Amigara Horrors and the Amigara Fault. When the Miners dug into the fault, the Government arrested them all and used them as test subjects. The Amigara Fault would be given a Classification Number, and the Horrors would be given a derivative (The Fault’s number with -2 on the end), as they are part of the same anomaly.
Additionally, the scientists used Death Row criminals for testing their experiments in Cataclysm. The SCP Foundation offers Death Row criminals a chance to reduce their sentence by working with the SCP Foundation for a month as “D-Class” personnel. Naturally, a large number of D-Class die before the end of the month and those who do make are just terminated (read: Killed) anyway (although some believe they’re just given Amnesiacs and moved elsewhere).
If you want, I can go more into some of the more notable SCPs, but this post is already long enough.