ultrashort SF story ideas: Posthumanity lives

Posthumanity met its first alien at the edge of the Local Group.
The dark matter entity could only be detected in the depths of intergalactic space.
It was so large that it didn't fit inside the observable universe, yet it weighed less than a virus.
Thanks to the Uncertainty Principle, interacting with this entity might allow time travel.

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6000 subjective years were spent studying the interactions of an incredibly specialized set of nanoscopic parts, that would probably never be needed.
Most submolecular interactions could be guessed from earlier tests and archived simulations in many unrelated fields. There were eight minor new sub-phenomena in the particle flows.
The knowledge would spread out at the speed of light, until it reached the same knowledge discovered independently elsewhere in the Conglomerate

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The God Bomb
Space itself still glowed, when the first great star in the universe pulled itself together out of mindless gas.
Its formation looked like a movie played in reverse. It seemed gravity could really reverse entropy.
After a few million years, it exploded again as an octillion cubic kilometer atomic bomb.
The birth of the quasar happened in layers and layers with complexity between them. Matter moved in weird ways toward circling horizons. The new black hole was the greatest galactic core in the observable universe.
Somehow the poles were calm. No matter entered where gravity was strongest. They seemed to rotate in opposite directions.
Before the cone collimator had spun up, here was the pathway to the core: a hyper-accelerating dive into a time wall.
The problem with the universe was that everything that happened, had to happen separately together. Everything that could be said to exist was connected.
Here of all places, in this region, that was most true. There were viruses in the structure of space-time.
Get through the torus to harvest its energy. From there you can reach a place where cause and effect sometimes get tangled. You can travel very, very far then.
The Universals were incomplete in a way that made them endless. They had been traveling forever, leaving subtle signs across space that made Ringworld look like a speck of dust.
In 2044, Posthumanity became able to see the stunningly artificial pattern behind all the galaxies in the universe.