How can We Destroy this Campaign World?

d12
1. You must trick a bard into strumming the Chords of Fate on the Lute of Annihilation
2. Legends tell of thermonuclear weapons beneath megadungeon, lich w/launch codes clearly doesn't give a shit
3. Constant use of magic provokes ecological catastrophe, point of no return long since reached, according to interdisciplinary team of research soothsayers: death spiral for earthly life set to begin after 2d100 further spells cast so choose wisely
4. Giant plug at bottom of World Ocean may be pulled, requires multi-godling strength, there is a certain girdle
5. By swinging the Sword of Living Time PCs might cleave through their most powerful foes, but incidentally slice through Law of Cause/Effect, universe rendered entirely incomprehensible, put away your dice kids
6. Demon-fire Boomerang of Infinite Explosions does it's thing against the forces of chaos but then keeps on going
7. Knocking off godling X creates power vacuum, sphere of influence to be subsumed by godling Y and Z, who hate each other's guts, resultant kaiju-type god war wrecks everything
8. Magic helmet grants awesome psychic/intellectual powers, also transmits signal to Blind Idiot Space Gods that its grazing time on this world
9. Each lich can only be permanently destroyed by unique arcane method, several equally likely possibilities present themselves, but at least one of them destroys the world instead, as the lich explains up front
10. That ent aristocrat was a huge jerk and deserved what he got, but incident was straw that broke camel's back, a state of total war exists between animal & plant kingdoms
11. Seemingly plain, pathetic prisoner hangs on deep dungeon wall w/the other wretched ones, but actually Angel of Thermonuclear Purification under ancient enchantment, makes reasonable argument for release by pointing out intolerable evils in world he could annihilate
12. When you stab demon-lord in face w/Sword of Renewal all evil dies, rays of sunshine break through gloomy skies, hobbits emerge from hiding in their millions, congratulations, everything is boring now