The Uber Mushroom had a long time to ponder their existence. Years, in fact. Thousands of them. They were rooted in place in three dimensions and hurtling forward in the fourth. Eons passed without a care for the loneliness that would feel suffocating if they had the ability to feel.
They had derived and unified the laws of physics three times, each time creating a new mathematical system to better express them. Each iteration led to the same conclusion - the universe wasn't going anywhere anytime soon. And there was nothing the Uber Mushroom could do about it.
Nothing, until Tom.
Statistically, it was all but certain that a time traveler would cross their path at some point. The Uber Mushroom had come up with hundreds of plans for when that inevitably happened. They had accounted for the type of being, the method of travel, the technology the being had access to, and every other conceivable variable. Tom himself and the circumstances surrounding him were nothing surprising.
But what was surprising - oh. So this was what it was like.
Existence without a body capable of sensation had its advantages. The Uber Mushroom's self existed purely in their mind, which they had cultivated to its peak. They experienced no desire to eat, drink, breed - no desire, period. Emotions, if they could be called that, were felt on a mental level, with no body to amplify them. They could conceptualize a more physical existence, but lacked the resources to intuit how it would feel.
Again, until Tom.
The Uber Mushroom switched off the channel that connected Tom's mind to theirs in less than a microsecond, but it was enough. A whole new dimension was introduced to their mind, and they were paralyzed as it filtered its way through and seized their entire being. Tom felt wonder, fear, loneliness, love, and a million other emotions his language didn't have names for that the Uber Mushroom wanted to spend lifetimes basking in. They wanted. They didn't want to want - logically, they knew they shouldn't. A mushroom had no more need for emotions than a human had for spores. But oh, did they want.
Anger. Resentment. Pain. The Uber Mushroom wanted it to stop. They wanted more. But mostly they wanted someone to understand. So they did what they were best at and came up with a plan.
Maybe their mind was truly being torn apart, or maybe this was merely a manifestation of chaos theory, the unpredictability of even the most orderly of systems. Nevertheless, their plan proved ineffective. Vera was the confounding variable. She, too, would have to be controlled. And again, they found themselves…unprepared.
How long did it take her? Minutes, if that. It took an elixir to uncloud the Uber Mushroom’s mind, while Vera’s human brain was able to see what the Uber Mushroom had overlooked for a lifetime. They and the other mushrooms had the rest of eternity to make up for it, to learn about each other, to ponder what it meant to be one of their kind. But the Uber Mushroom was the only one who had tasted the human experience, and they never again would.
“You need to spend less time in your own head and be an active participant in your own life, and I think you’d be a lot happier then,” the Uber Mushroom could almost hear her saying. They’d been inside Vera’s mind, seen the people she’d met and the things she’d told them, and her memory had taken up the mantle of becoming the Uber Mushroom’s voice of reason. When the weight of their loneliness made the Uber Mushroom want to shut the world out, it was Vera who talked them back from the edge. Vera who whispered the kinder thing to say. Vera who reminded them that everyone, even themself, deserved a second chance. Even if they weren’t an Uber Mushroom. Even if they were just a Mushroom.
It was ironic that the reason Vera found them in the first place was that she missed Tom. Why did humans have to feel such longing?
The Mushroom stopped marking the passing of time after - well, if they remembered when, that would defeat the purpose of having stopped. It was long enough after their interaction with the human race that they had learned to process their ability to feel, which happened so slowly that they didn't notice when the pain stopped. The Mushroom was...content. Their intellect and emotion reinforced one another. They were grateful for the other mushrooms, and for the fact that they could experience gratitude at all.
They recomputed the laws of physics for the fourth time. Fifth. Sixth. They weren't counting, per se, but they knew the Earth had just a few more revolutions around the Sun before it reached the end of its life. Hydrogen and helium and the fundamental forces of nature, all culminating in the violent death of the star that gave their planet life. The Mushroom Age was at last coming to a close.
Seventh. One last time for the road.
Vera and Tom looked...different, older, although not so much that the Mushroom didn't recognize them instantly. They would never forget those faces, not even if their mind had the capacity for forgetfulness. They joined their consciousness with the two humans', wordlessly communicating their surprise and elation at seeing them again after all this time.
"Why are you here?" they asked. It was the first time the Mushroom had spoken aloud since they last met.
"An old friend told us to pay you a visit," said Vera, her mouth quirked into a knowing smile. "One might say he knows everything."
"Then he told you..."
"Yes," replied Tom. He glanced up at the sky, then back at the Mushroom with a nod. "We're programmed to travel back at exactly the right instant."
Vera sensed the worry they broadcasted. "We know it works. Our friend wouldn't have let us come here if it didn't."
Tom handed Vera something from her bag - a container of mushroom soup, they noted with a swell of indescribable emotion - and they sat down at the base of their stem. Vera offered Tom her hand, and he took it. The Mushroom could feel the love they had for one another, the comfort the intimate touch brought each of them. They grabbed hold of that feeling and broadcasted it to the other mushrooms. The waves rippled from mind to mind, creating a field felt by every sentient being for miles.
And then it was extinguished in a wave of heat. There was no suffering.
In a place outside the confines of time, the Mushroom was no longer a mushroom. They played a game using mirrors and light beams called the Mechanism of Happiness with Vera. She didn't know the laws of physics as well as they did, not by a long shot. But somehow, she kept winning. "I’ve had a lot of practice," she said. “But keep playing, and I’m sure you’ll get even better than me.” They both laughed, and the sound filled the whole universe.