Universe 25 was a 101-square-inch tank, carefully engineered to safely and comfortably hold over 1,000 mice. Everything was provided for a little mouse heaven, but it's like Rodent Sartre said: Hell is other mice.
There were only four breeding pairs at first, but then nature took over. When Universe 25's population reached 600 mice -- not even close to capacity -- growth began to slow. At a staggering 2,200 mice, twice the maximum comfortable occupancy, growth of Universe 25 stopped altogether. But it was too late; the environment could not regulate. Living with such overcrowding had ruined the mice psychologically. Without normal designated tasks like protection and food gathering, the mice became psychotically, randomly violent. Or else they turned into something worse: One of the ominously dubbed "Beautiful Ones." The Beautiful Ones didn't want sex, they didn't want to fight, they didn't want anything -- the world started destroying itself around them and all they did was eat, sleep and groom themselves. With the only potential mates being rage virus psychos or impotent, navel-gazing egomaniacs, all breeding stopped, and Universe 25 collapsed completely.
Are those ... are those tiny furry heads mounted on those spikes?
But it was inevitable, really. The clue was in the name: What do you think happened to Universes 1 to 24? Tiny mouse apocalypses were such old hat to Calhoun that he'd even devised an algorithm for it. This is it:
Mortality, bodily death = the second death
Drastic reduction of mortality
= death of the second death
= death squared
(Death)2 leads to dissolution of social organization
= death of the establishment
Death of the establishment leads to spiritual death
= loss of capacity to engage in behaviors essential to species survival
= the first death
(Death)2 = the first death
Jesus, dude. When you're constructing the algorithm for the perfect society and you start factoring the "drastic reduction of morality" and carrying the "death of the establishment," maybe it's time to check your back for some kind of purple cape: You might have finally crossed that fine line between mathematician and supervillain. But what did that morbid algorithm end up proving, anyway? That mice suck at building societies? You don't need math to prove that shit, Calhoun; just open up the cages at the pet store and see how long it takes them to start running the register. What's that? They're not doing it all? They're just pooping? Everywhere? Right, because they're friggin' mice, man.