An experiment to create super-powered soldiers goes wrong as the soldiers start using their power to take over the world, not necessarily destroying the world but creating a power influx where everyone not 'super' was bottom of the barrel.
Timeline - 6197V
Giant cockroaches were given the ability to read. This universe was erased by "AE" a superior God because he didn't understand why that existed.
Timeline - ???
Aliens came down to Earth, trying to research but humans didn't receive them with open arms. Killing the first two alien UFO envoys, thereby starting a war between mankind and Alien kind. A war mankind would lose when a gamma ray was fired at Earth. (Note: this gamma-ray had the power of 6 million nukes)
Timeline -476L
Humans scattered across the fields as meteors graced the grounds, they crash-landed and exploded releasing blasts of fire that burnt and instantly turned humans to ash and the ones that got hit by it were smushed into the ground like cheese on bread.
Timeline - 122b
Humans had feared this day since the beginning, the artificial intelligence they had created to serve them had hacked their satellites and weapons. Using it against them, ultimately destroying all organic life on Earth. Creating a world of only androids and robots.
Timeline - 6678J
A deadly virus was released from a lab in Hungary and from it the end of the world was certain, the virus infected humans through air and touch. It was fatal, within a few minutes your lungs would collapse and your heart would stop. Half the population dropped and humans found shelter underground. This worked for about three years until the virus evolved, the pathogen could contaminate the water supply and gas masks no longer filtered it out. The remaining half dropped just as fast as the first immediately one person became contaminated.
Timeline - 239Z
Wars raged on in the world, after the fourth world war Iran had unleashed a nuke that would shake the earth's core ultimately leading to the death of its people.
Timeline - 126G
A crossbreed between a cheetah and a lion created an animal so rabid they killed humans on sight, they bred with other animals passing on their genes until their population became just under half the population of the world, they devoured humans until several nukes were used to destroys all the areas to the south. Where they were most sighted.
Timeline - 35C
Scientists experimented on a multi-cellular organism that eventually evolved creating a beast that devoured everything in sight. Nicknamed "Aragami" the foul evolving beasts devoured humanity until survivors used the aragami core to create a weapon.
Timeline - 453 G.E.
The ozone layer cracks releasing harmful rays that eventually destroy all life.
Timeline - current- Earth.