- "When I saw you stop the world from, you know, ending, I just assumed that was a big week for you. It turns out I suddenly find myself needing to know the plural of apocalypse."
- ―Riley Finn[src]
An apocalypse was a specific occurrence which had an exceptionally destructive effect on the human race. The final outcomes of doomsday events varied from a major disruption of human civilization, to the extinction of human life, to the destruction of Earth, to the annihilation of the entire universe.
Several events that almost caused an apocalypse were averted thanks to the efforts of the Scooby Gang and the Angel Investigations team. However, the end of magic not only came to pass, but was actually caused by its respective leaders Buffy and Angel.
- Opening of Hellmouth by the Order of Aurelius.
- Possible use of nuclear missiles by Moloch.
- Opening of Hellmouth by the Master.
- All of humanity being incinerated by the Judge.
- World being sucked into Hell by Acathla.
- Vampire supremacy in the Wishverse by the Master and the Order of Aurelius, already effective on Sunnydale.
- Opening of Hellmouth by the Sisterhood of Jhe.
- Ascension of Richard Wilkins into Olvikan.
- Destruction of all human life by the Scourge and the Beacon.
- Opening of Hellmouth by Behemoth and two other Vahrall demons via the Sacrifice of Three.
- Adam's creation of an army of human/demon cyborgs.
- Freezing of time by Gene Rainey.
- Opening of dimensional portals by Glorificus, bleeding all dimensions together in the Big Day.
- The death of all living creatures due to the loss of the Sun.
- The First's endgame: the possession of mankind en masse and the destruction of the Slayer line.
- Complete loss of free will to Jasmine.
- The release of Illyria's army of doom upon humanity.
- Destruction of the North American continent by the self-destruction of Illyria.
- Wolfram & Hart's scheduled Apocalypse.
- The Fall of Los Angeles.
- Opening a little Hellmouth by Tansy Fry and her new Order of Aurelius in Los Angeles.
- Earth being transformed into a demonic breeding farm by Myresto Mor.
- Destruction of the Earth dimension and creation of the Twilight dimension in its place.
- The destruction of the Seed of Wonder, causing the end of magic.
- Re-opening of dimensional portals by Wolfram & Hart's TinCan website.
- Reversion of Twilight by Severin, which would tear reality itself apart.
- Outbreak of a mystical plague caused by Whistler, Pearl, and Nash.
- Hostile interdimensional demons filling the Earth through the Restless Door, in power of the Mistress, the Soul Glutton, and the Sculptor.
- Merging of the dimensions of Anharra and the Earth.
- D'Hoffryn's elimination of the power restrictions from vengeance demons.
- Archaeus's command over an army of vampires and the new magic from Magic Town.
- Pandora Project's success in absorbing all magic from all supernatural beings, leaving the power of a ruler to Joanna Wise.