 This list is unofficial in every way, it's basically non-canon, and an SCP canon is what you make of it. Basically, it's a head canon. If you're interested in it, if you're an author that writes for SCP or want to write for SCP sometime, check out the Read Me link I've put down in the description, and it offers a lot of advice for people who want to write for SCPs, and a bunch of author notes and general advice, so I'm kind of skipping over that, so I'm just going to get right to the K-class list. A-level scenarios, generally accepted site-wide, appears in multiple SCP articles, Foundation tales, or one well-received, well-known, permanent resident article or tale. A-K-class, end-of-the-world scenario, description, end-of-the-world via restructuring of subjective reality, that is, the perceptions and or thought process of the human race, simply put, everyone goes crazy by one fashion or another. Moose's Notes Multiple references using similar definitions have appeared independently of each other in various works. This can be thought of as a restructuring scenario, but it would typically be termed as an end-of-the-world scenario because effectively for humans, the world has ended, just as thoroughly as if civilization got all blowed up. Appearances Change Scenario is first referenced and established as a scenario involving reality shifts related to BK-class undefined and CK-class restructuring. SCP-571 Scenario is- SCP-571 Scenario is the permanent alteration of behavior in all or the vast majority of the human race, caused by a memetic pattern with a piggybacking anomalous effect that forces the user to permanently fixate on spreading it. SCP-1101 Scenario is a perpetual argument encompassing all or the vast majority of the human race, caused by a mind-altering device with an exponential effect. SCP-1101 CK-class restructuring scenario Definition Restructuring of reality may mean a significant change in history, rewriting the present to match, or a change in the way physical laws work, or in the way the universe works, or a major rewriting of reality encompassing some or all of these. Moose's Notes The original restructuring scenario may have been created by an ex-site member and called CK-class reconfiguration, but as their work no longer exists, their usage of it is irrelevant. The only used one CK-class in the world scenario may be a subset of this scenario, see below. Appearances SCP-140 Scenario is retroactive restructuring of modern society based on alterations to timeline. Of multiverses of dandelion wine. Scenario in which the multiverse is collapsing, universes merging together. SCP-239-B Cliff Kondrackie SCP-239 Scenario is a reality-bending, rewriting reality as we know it. SCP-1237 A wide variety of wide-scale non-apocalyptic reality shifts. Change Scenario referenced along with AK-class and BK-class scenarios is one of three scenarios involving reality shifts. Recovered data file Scenario involving multiple CK-class events. Some deliberately initialized by the Foundation, apparently attempting to repair or control an ongoing restructuring scenario. GH-class Dead Greenhouse Scenario Definition Life as we know it is 80% or more dead, but the planet can still be fixed more or less and can still support life. Moose's Notes Also referred to as DG-class Scenario unofficially by author Dr. Gears in discussion. Appearances Document recovered from the Mariana's trench. Scenario is near total SCP containment breach, causing widespread destruction and chaos in which most of humanity dies, and the Foundation must rebuild the world to an approximation of what it once was. Referred to as GH-0 NK-class End of the World Scenario Definition End of the world caused by self-replicating material. Moose's Notes, also referred to as the Grey-Goo Scenario, once defined as a scenario characterized by an explosive event with effects on a geological scale. This definition can be considered defunct, as the current definition has been widely accepted and the earlier definitions seem excessively specific. Appearances SCP-505 Scenario's massive-scale environmental contamination caused by self-replicating ink. RK-class Restructuring Scenario Definition Outcompetition of Standard Earth Species by Non-Standard Life Forms Moose's Notes, definition taken from SCP-816 and thus may be excessively inaccurately specific. Alternates suggested definition. World is changed but humanity, history, and rules of reality are the same. Appearances SCP-816 RK-class Dominance Shift Scenario Definition Changing of the planet's dominant species Moose's Notes, in the modern day, indicate the shift to dominance by another life form or humans of alternate form and or culture. Appearances SCP-752 Scenario's competition between modern-day humans and genetically socially re-engineered humans projected to results in dominance shift. SCP-1000 Scenario is shift in which humanity becomes the dominant species of Earth by driving another species to near extinction and destroying their civilization semi-permanently. RK-class End-of-the-World Scenario Definition Salted Earth End-of-the-World Scenario, in other words, destruction of the world as we know it with little possibility of immediate rebuilding, may include but is not defined by threat of species extinction. Moose's Notes, the original End-of-the-World Scenario, formally meant a religious apocalypse in line with some variant of Abrahamic religious beliefs, usually as a direct result of a major religious event or artifact. Expanded further to the above definition, this term is also used as a shorthand or slang term for all apocalyptic scenarios. Appearances Dr. Kles' proposal for SCP-001 Scenario is a biblical apocalypse of some variant. SCP-152 Includes many XK-class scenarios that involve the extinction of humanity, specifies that apocalyptic events that involve the extinction of humanity are not all classified as XK-class scenarios. Revised Entry to SCP-173 SCP-173 involves alternate universe version of SCP-173 getting the ability to multiply with a hive mind, wiping out most of the human population of North America, South America, and the United Kingdom, followed by saturation nuclear bombing. SCP-227 Two example XK-class scenarios are given, wondering Brown dwarf the so-called Nemesis Hypothesis, or a gamma ray burst. Other apocalyptic cosmic events that are classified as XK-class scenarios are implied. SCP-231 Scenario involves a satanic cult-induced pregnancy, serving as a seventh seal, being ended or carried to term resulting in a supernatural religious apocalypse. SCP-435 Scenario involves SCP-435-2, the shadow of an extra-dimensional entity, causing massive widespread destruction on a nuclear detonation scale at minimum, to start, prevented only by keeping SCP-435-1 under bright light. A last resort preventative is contingency 435-XK-alpha. SCP-616 Fictional procedure involves destruction of supposedly Abrahamic religion-based SCP in event of any XK-class end-of-the-world scenario. SCP-701 Specifically not an XK-class scenario, only kills hundreds of people a year. SCP-861 Variety of scenarios based on Judeo-Christian religious beliefs refers to XK-400 and XK-423 through XK-436. XK-400A involves YHVH, XK-440-C through XK-440-V involve either the seven seals or entities associated with the seven seals. SCP-861 is preliminarily designated XK-440-X. XK-423 involves Leviathan. SCP-923 Scenario involves permanent alteration of landscape decree insanity in addition to severe spatial and temporal disturbances and various other worst classified effects, including materialization of something classified. SCP-1023 Scenario involves the detonation of a record number of nuclear detonations within a short period of time. SCP-1200 References an apocalyptic scenario that can be prevented by containing and manipulating the cognitive patterns of SCP-Redacted, a human child possibly SCP-231-7. SCP-1237 Used to refer to a variety of possible apocalyptic scenarios caused by rewriting parts of reality via dreams, as distinct from the CK-class scenarios considered more likely to result. SCP-1591 Scenario involves a device that could theoretically dissolve the entire Earth and certainly the organisms on it. Stratagem SCP-008 Release of SCP-008 zombie virus said to likely result in an XK-class or XC-class scenario. The Sleep Per Chance to Dream Scenario involves using protocol XK-0272A as a reaction to a mass potentially species-wide deadly infection. Protocol requires destruction of all major worldwide population centers. Shorthand and slang references may not actually be technically classified as XK-event scenarios. SCP-096 Scenario involves near-unkillable creature breaching containment and killing the majority of the human species, likely slang. SCP-108 Used to refer to all apocalyptic scenarios SCP-523 Used to refer to all apocalyptic scenarios SCP-630 Contamination of water supply which would term warm-blooded life into black, non-reflective, blind, heat-seeking zombies is referred to in a researcher note as a kind of XK-event, likely slang. ZK-class Reality Failure Scenario Definition Reality Failure May or may not be the only one of many realities, may include end-of-all reality Mooses notes, proposed multiple times before finally being used always in the same sense Appearances S. Andrew Swann's Proposal for SCP-001 Scenarios to Possible Failure of the Foundation's Reality B-level scenarios, used in a less well-known SCP article or Foundation tell, or vaguely defined but used in multiple pieces BI-class Biological Invasion Scenario Definition Invasion of Earth by extraterrestrial lifeforms Mooses notes, implies some kind of distinction between extraterrestrial biological and non-biological invasion, not widely accepted but potentially usable Appearances The Bacterium Part 1 Part 2 Finale CK-class End of the World Scenario Definition End of the World via wide-scale or total restructuring of the physical mass of the world Mooses notes, seems to be a specific subset of the CK-class restructuring scenarios Appearances SCP-1053 SCP-1012 EK-class Undefined Scenario Mooses notes, does not end human life possibly destroys society, possibly destroys most or all of human consciousness Appearances SCP-338 A loop recording of survival instructions, rendezvous locations and status updates about the Great War, and seems to describe an EK-class scenario caused by the release of SCP-blank. The contents are changed and updated sporadically, ranging from twice daily to once every three weeks. SCP-1427 involves extinguishment of all human consciousness within approximately 215 days. EK-class Collapsed Global Civilization Scenario Definition Collapsed Global Civilization of a fashion that does not fall under another scenario Mooses notes, scenario did not originally imply any SCP containment breach, just any truly massive natural disaster, later expanded to be defined as Global Civilization Collapse, often caught by natural disasters on a massive scale Appearances SCP-1238 Scenario is a partial collapse of continental plates that would destroy major population centers In the Big League, scenario is an asteroid strike with estimated casualties of approximately 3 billion over 10 years. C-level Scenarios Used in an SCP article or Foundation tale but undefined EK-class Undefined Scenario Mooses notes, explicitly related to EK-class undefined or CK-class restructuring, dislike the others of the scenario involving reality shifts, likely a restructuring scenario Appearances Change EK-class Undefined Scenario Mooses notes, probably a redundant class at this point uses a throwaway and not necessarily very usable, alternatively a C-class scenario could reflect a partial K-class scenario For instance, an EK-class scenario could be the destruction of a specific subsection of humanity, say with genes that made them susceptible to a certain anomalous thing while the rest of humanity survives. Appearances Stratagem SCP-008 Results from an SCP-008 outbreak, EK-class scenarios suggested a similar likely alternate result D-level Scenarios Unused but proposed or referenced multiple times in discussion These definitions have a tendency to change EK-class Vacuum Decay Scenario Definition Vacuum Metastability Event Wiping out all life in reality Mooses notes, proposed by The Raven, used only in a deleted article, seems a bit overly specific