When it notices the bottom and edge, it hops out, and nudges into the edge from all around, then hops into and out of the water a few more times. It gets out, then tilts its top prism at him and the rest of his water.

(He can feel some crystals or something starting to grow in his larger collection of water.)

Well that is frustrating because he wanted a useful source of water all for himself and this feels like he might be killing some children or something if he tries to get rid of them.

He tries to get them to stop growing by separating the water into smaller groups. Also, if that doesn't help, he makes the whole water stick in place, unmoving with quite high precision.

They continue growing when the water is separated, but stop once the water is unable to move at all.

He thinks he will keep the water around the crystals solid, then extract the rest of the water from around them, removing the impurities as he does so.

Ew.

The separated impurities form a glowing blue goop, with some tiny specks that feel a little bit like the beginnings of more crystals, although they don't seem to be growing.

The stack-thing tilts toward the little crystals, and the separated water, and chirps again.

Tyler doesn't understand, he's afraid. And if the stack thing wants them recombined, he'd rather not, thank you.

The stack thing hops back and forth and tilts at the crystals and goop and clear water, then buzzes and hops back onto its seat.

Tyler moves the crystals and goop and a small amount of the clear water towards the other pool for the stack thing.

It hops back down. A thin sliver of one of its middle prisms curls out and pokes at the clear water, then at the goop.

The stack-thing trills and jumps onto the goop.

Yay for the stack thing.

Tide's just gonna wait here quietly and, like, leave stuff for the stack-thing to play with.

It jumps around in the goop and water, then pokes some more at all of the substances. After about ten minutes, it stops, chirps at him, and hops back onto its seat.

He'll leave the stuff there in case it wants it later.

Does it do anything interesting back in its seat?

It stands still for about ten minutes, then hops to the front of the car, by the window. After about five minutes, it hops past him to the back of the car.

Aww. It's almost cute.

He'll go play around on his phone some more then. Ugh. He can't even properly relax because he has to be aware for if the stupid subway car does something he's not expecting that he needs to react to.

Oh well.

The car keeps going through nothingness. After fifteen more minutes, the stack-thing buzzes and hops back to its earlier seat.

Still almost cute.

He watches it for a short bit, then gets back to his phone.

It sits in its seat. After another ten minutes it spins some of its prisms completely around, and buzzes sort of melodically for a few minutes, then stops and holds still again.

The darkness outside the car seems - closer? It's still impossible to see out of, but it seems like it might be moving.

… That's curious enough that he decides he will watch the darkness instead of his phone.

Despite still being just utter empty blackness, there is a definite impression that the darkness is crawling, or dripping around the windows.

The stack-thing buzzes and hops up to him, uncurling a ribbon of its side and leaning toward him.

Aww.

He keeps some water near him just in case he needs to defend himself.

There is a distinct impression that the darkness is infecting something, getting inside of things and turning them into more of the crawling darkness. Perhaps it's a good thing that the doors are so difficult to open.

The stack-thing leans into him, and curls a few of its ribbons around a pole.

… He keeps his collections of water on-hand, prepared to direct them against something if necessary.

Weird darkness giving him a weird impression of infection. He's pretty sure darkness doesn't do that normally even if it is infecting things.

A sense of wrongness, of contamination, the darkness seeping into everything within it, pressing against the seams near the windows and doors, but not finding an entrance.

It seems to stop, and settle around the car, unmoving.

After about half an hour, there is an impression of darkness dripping away, running down the windows and falling past the car.

Well at least this weird subway car seems airtight, albeit extremely weird and also bizarrely difficult to damage.

After a few more minutes, it feels like they're out of the contaminating darkness, and back in the boring empty darkness.

The stack-thing relaxes its wrap around the pole, but continues leaning against him.