The Antediluvians destroy the world in their struggle, and drain all life to fuel their quests for godhood. All of humanity dies. All the animals die. All the plants die. Everything in the sea dies. Only the characters are left, the last dwellers on a planet as barren as the moon. They have nothing left to feed on, except each other, and then - a torpor that never ends, or the mercy of the sun.
—"And The Rest Is Silence", Vampire: The Masquerade: Gehenna
The grey goop swept across the Earth, leaving behind grey dust. The nanomachine swarms scoured all organic matter from the Earths surface, even delving into the crust to leech out coal deposits, diamond, and all manner of carbonate rock. The surface is not only devoid of life, but lacks the necessary foundations for life to ever again take hold.
Most of the Earth is now largely featureless wastes. Once-lush areas are reduced to silicate dust. Bodies of water, too, are polluted with the chemically unstable remnants left by the nanomachines. Even a slight wind stirs up choking dust. A relative handful of survivors struggle to survive in this environment, people who somehow escaped the nanobots thorough harvest.
—"Nanopocalypse - Post-Apocalypse," The End of the World: Revolt Of The Machines
If even a quarter of Typhon's mass hits as a single body, the impact propels the Australian continental plate and a significant amount of Earth's mantle into space, where it eventually coalesces into a smaller second moon. The oceans are immediately vaporized, and the tectonic plates surrounding the impact site are melted back into magma. All others are utterly shattered, bobbing on the magma sea. Earth's evolutionary clock is almost completely reset. The last time it looked like this was just under four and a half billion years ago, shortly after its formation from interstellar gas and dust.
—"The Earth Will Shake," Mage: The Ascension - Ascension
By the end of the Dark Crusade, Kronus was a tomb world once more. Just as the marching Necron armies cut down all their opponents, so did other fiendish devices work on the planet's very ecosystem: scarab swarms scoured the lush jungles of the south and the fertile plains of the north, while pulses of loathsome energy killed even microscopic bacteria. The seas died and the air itself became rarefied and poisoned. Soon, sterile sand and dust swept across the Kronusian landscape, broken only by black monuments to the Nightbringer.
—The Necron Ending, Dawn of War: Dark Crusade
Brigade Leader Lethbridge-Stewart: Well, Doctor, what is going to happen?
The Doctor: Well, the heat and the pressures will continue to build up until the Earth dissolves in a fury of expanding gasses, just as it was billions of years ago.
Elisabeth Shaw: How long have we got?
The Doctor: Maybe a few weeks, maybe only a few days.
First Officer's log, stardate 4124.5: we have found Data's home to be a completely dead world, down to lifeless vegetation. No insects, not even soil bacteria. What is it that could kill everything on an entire planet?
My homeworld still exists. It is... intact. The planet was not destroyed, it remains... it orbits, dead in space, but nothing lives on its surface. It echoes, but there is no one left to hear it.
—Visas Marr, Knights of the Old Republic II: The Sith Lords
Day 80: Ripper swarms, having systematically divested the land masses and basolithic planes of soil and dermis, board the brood ships and return to space. Once this has been completed, the huge hive ships descend into the upper atmosphere. These creatures, which resemble primitive, radiant life forms with long tentacles, the drop into the atmosphere and begin removing it. As the atmospheric pressure is reduced, the water of the oceans begins to evaporate, and it too is vacuumed up. As the tectonic planets begin to move due to the shift in planetary pressures caused by the removal of the vast oceans, volcanic activity increases. Devoid of the huge weight of the oceans, many areas rupture, spewing hot gasses and lava onto the surface. As the hive ships take the last remnants from the planet, they retreat into the warp, leaving the barren sphere in its death throes.
Day 100: Imperial Navy arrives in response to the distress call, finding the planet lifeless.
—"Tyranid Planetary Assimilation Analysis", Warhammer 40,000