Bonesaw- Miasma Intro

I turned back to the subject at hand, “We can’t guess what she’s come up with because her tinker abilities make her so versatile, and that means we can’t preemptively set up any countermeasures.”

Tattletale tucked her hair behind her ear.  “Fits in a vial, assuming that vial she was showing off was the real weapon, something to do with water, she said… you guys haven’t been drinking anything except bottled water?”
...

“Heads up!”

I wasn’t sure who had shouted the warning, but I turned to look in the direction of the fighting, and I instantly knew it was Bonesaw’s work.

The water was turning crimson.  Where it was only one or two inches deep above the pavement, it turned a dark red that resembled blood.  That alone might have been spooky enough, but it was spreading over hundreds of feet in a matter of seconds, and there was a thin red mist rising in its wake.

“Run!”  Grue shouted.
...

I needed only one glance to know they weren’t running fast enough.

“Sundancer!”  I shouted.  “Cut it off!”

It took her three or four seconds to pull an orb together, no larger than a basketball.  It grew to twice the size as it flew, raking across the street to turn the pooled water into clouds of steam.  I rose higher in the air to avoid being caught by the plumes of hot water.  The steam turned from a clean white to pink and eventually red as the effect reached it.

Sundancer’s miniature sun had slowed the progression down our flooded street, but it wasn’t enough.  From my perspective, I could see the water on adjacent streets undergoing the same transformation, moving forward until it was adjacent to the others, then extending forward.  It was a matter of time before it reached far enough forward that it passed through the side alleys and cut them off.
...

It was too slow.  The water turned crimson beneath him, and then the vapor began to rise, faster than Bentley was climbing.

“Tattletale,” I breathed.

I massed thick clusters of bugs between them and the vapor, while Regent and Shatterbird followed Sirius and the others.

It was enough to buy them time, but that meant precious little.  No matter how much I pressed the bugs together into an airborne barrier, the vapor made its way through.  Worse, the mist was rising to either side of them, approaching the top of the building.

They reached the rooftop and Bentley heaved himself over the edge.  They hopped off his back as they reached solid ground, and Tattletale stepped over to the corner of the roof to watch the rise of the red vapor.  It was only a floor beneath them.
...

He and Trickster reached the second rooftop quickly enough.  The mist was still rising, not just below us, but up around buildings nearly as far as the eye could see.

“Shit,”  Tattletale said.  “Not good.”

“There’s a taller building over there,” I pointed.  “We should head there before the mist gets up here.”

“I’d call it miasma,” Tattletale said.  “And is there really any point?”

“It might stop rising,” I protested.

“It won’t.”

“Is that an educated guess or-”

“It’s not.”

I found myself at a loss for words.

“What does it do?”  I asked.  “Poison?  Something else?”

“Probably something else.  Or it’s poison, but it’s designed to do something besides kill us.  How are the others doing?”

- Worm, Prey 14.8