The Sludge-Beast walked step-by step out of its dolorous shack. It blinked at the daylight. It oozed, perhaps a little sadly.
These were all things that Sludge-Beasts commonly did - when there were Sludge-Beasts, that is.
They thrived in meadows and hills! They swam in the oceans, they galumphed across the plains! Some - a very lucky few - even soared across the sky by means of swift-spinning sludge-propellers, leaving vast trails of sludge behind them wherever they went!
Those were the days of the Sludge-Beasts.
But then a Sludge-Beast made a discovery. It reached deep into its black, suppurating chest cavity - feeling around for the sludge-morsel it had stashed there earlier in the day. But it pulled out something altogether different! Something furry - warm - adorable! Not sludgy at all!
The Sludge-Beast stared at the creature in its sludge-tentacle. "So beautiful!" it thought. "To think that such a thing could come from an unworthy creature like me!"
Then it died, and melted into the earth!
(Not because it had gotten depressed. Because the creature, prior to being pulled out, was functioning as the Sludge-Beast's beating heart. This is one of many reasons it is unwise to store objects in a suppurating chest cavity if you intend to retrieve them later - you might pull out your heart instead!)
It might have ended there, had two other Sludge-Beasts not been nearby. But they were, and they saw, and they thought. "How beautiful a creature our brother-sister pulled from itself!" the two Sludge-Beasts thought, more-or-less together. "That we, crude and malformed creatures that we are, might harbor such within ourselves, contained only by necessity of powering our own lives? How can we justify our own existences?"
One of the Sludge-Beasts thought about this. It stared at itself. "Enough!" it wailed, a hideous screeching cry, and tore from itself its heart. Then it was no more.
But the other Sludge-Beast justified itself. "I am unworthy to live," it reasoned, "except by this: that by my existence, I will go forth to all my brother-sisters; I will tell them what lurks within their heart. Then - only then - will I end myself!"
And so this Sludge-Beast, emerging from its ichorous hut, found itself entirely alone in the world.
It was not surprised by this, really. It had sensed its brother-sisters snuffing themselves out for some time. That the last one had done so - well, it seemed inevitable!
But now the Sludge-Beast needed to justify itself.
"Why should I live?" it thought. "What value is there in me, even as the last of my kind, when something so much more beautiful lies waiting inside my heart?"
It stood there for some time.
Sludge leaked onto the ground. A black pool formed. A bird landed; pecked at the pool; recoiled and quickly flew away.
Then the Sludge-Beast reached a conclusion. (It hadn't noticed the bird. That was a detail added to create the impression of time's passage, not a major part of the narrative.)
"Why should I live, when my death would so improve the world?" the last Sludge-Beast rephrased.
It shrugged, a long, rolling shrug, sending waves of goo out to spatter on nearby trees.
"Eh," it thought. "What did the world ever do for me?"