They are listed in order by how destructive/dangerous each scenario is.
K-Class Scenario
Among the scenario classifications, K-Class Scenario is defined as the 2nd highest threat Scenario, where a SCP of high danger breeches the facility and/or cannot be contained and is a threat and high priority of the SCP foundation to recontain/neutralize this SCP.
XK-Class Scenario
An XK-Class Scenario is a scenario in which an SCP of world ending properties or worse is in a unpredictable state, and it becomes top priority to the SCP foundation to contain this SCP or neutralize it, if neither of these is optional a SCP like SCP-2000 must be used as a final resort to the scenario.
Class Scenario Definitions
| Scenario | Type | Definition |
|---|---|---|
| GK-Class Hostile Greenhouse Scenario |
An event where plant life would severely disrupt the planet. | |
| EK-Class Undefined Scenario |
Does not end human life, possibly destroys society, and possibly extinguishes most or all of human consciousness. | |
| RK-Class Restructuring Scenario |
An event where standard Earth species are outperformed by non-standard lifeforms. | |
| AE-Class Allison-Eckhart Breathability Scenario |
The Earth is fully contaminated in gaseous anomalous (or non-anomalous) substances. | |
| BI-Class Biological Invasion Scenario |
Invasion of our planet by extraterrestrial life-forms; An alien invasion. | |
| GH-Class Dead Greenhouse Scenario |
80% of most living organisms, more or less, has been wiped out, but the planet is still in repairable condition, and can still support life. | |
| IK-Class Collapse-of-Global-Civilization Scenario |
Collapse/destruction of global civilization. Normally caused by natural disasters on a massive scale. (Meteor strikes, solar flares, continental shifts, etc.) | |
| XK-Class End-of-the-World Scenario |
Destruction of the world, with little to no possibility of rebuilding and reparation. | |
| CK-Class End-of-the-World Sccenario |
Wide-scale (or total) restructuring of the physical mass of the world; Destruction of the planet. | |
| NK-Class End-of-the-World Scenario |
The end of the world caused by self-replicating substances. | |
| BK-Class Undefined Scenario |
A scenario involving reality shifts. | |
| AK-Class End-of-the-World Scenario |
End of the world via remodeling of subjective reality. Can also be thought of as a restructuring scenario. | |
| ZK-0 Reality Failure |
An event in which the universe will continue to exist, just under entirely different laws. | |
| CK-Class Restructuring Scenario |
A reconstruction of reality. May mean a significant change in history, a change in the way physical laws work, a major rewrite of reality, or possibly even all of the above. | |
| YK-Class Entropic Annihilation Event |
An event that causes the entire universe to reverse its flow of entropy, converting the universe into a inverted entropic state, eventually resulting in the greenuction of the entire universe to an infinitely energetic singularity (An inverted BIG BANG). | |
| YK-Class Vacuum Decay Scenario |
A vacuum metastability event, wiping out all life and reality. | |
| ZK-Class Reality Failure Scenario |
The destruction of one or possibly more realities. May also be used to refer to the end of all of reality itself. |