It was when Irving was using his three in one shower gel that the world changed.
Specifically, the world changed the moment that Irving turned off his shower.
Irving loved his three in one shower gel. No longer did he need to get shampoo, body wash, and shaving cream. He could use this one thing for all the other things, and it worked beautifully.
When he was done showering, he realized that he had forgotten to clean some of the three in one gel off his leg. He rubbed the gel into his skin was about to turn the shower back on, when he felt it sink into his skin and moisten a dry patch below his knee. There was no soapy residue; it was the best moisturizer he had ever used.
Spurred on by this discovery, Irving set out to discover how many other uses there were for which he could use what was now, for the moment, a four in one lotion.
He soon discovered the the lotion also allowed him to clean the bathroom mirror so that it never again fogged up. Next he discovered that all he needed to do was rub the lotion into the windows and it would clean them with no streaks. It seemed as if the lotion had a kind of psychic smart molecule composition, where it changed according to the use that the lotion owner was thinking about.
Irving told his friends about the seemingly endless uses of the lotion—which by now, he called an all in one lotion—and as word spread, people across the world began to have lotion parties where they exchanged ideas for lotion use. These ideas made their way to websites, and soon, across the world, people were using the lotion for a variety of purposes.
Carpenters discussed how they could put it on paper, stipple it, and make a sandpaper far better than any they had previously used. Mechanics discussed its lubricating powers on valves and crankshafts. Doctors discussed its antiseptic qualities, and the way it cleared arteries of deadly plaques.
It was not long before chefs were using the lotion as an ingredient in their dishes. Soon, however, people complained that all the other ingredients obscured the taste of the lotion, which made people close their eyes and think of the best moments of their lives. Crime rates plummeted as charitable organizations dispensed the lotion to the poor, who were inspired to work their way out of their dire circumstances.
The lotion, however, was fiercely addictive, and when the recipe became public—which revealed that that the main ingredient was human brains—people turned against each other cracking skulls open. Then, with brains in hand, they would run home to make another batch of the lotion.
Not even newborns were safe, and within months, there weren’t any people left under the age of ten.
Those left continued to kill each other, and thoughts of reproduction disappeared. Eventually, the last human on earth died after trying to crack his own head open to eat his own brains. Then the aliens who had beamed the recipe into the head of the man who mistakenly believed that the recipe was his own invention landed on the planet, and began their colonization.