Mist illusion

I needed to lure them in closer.
“Grasshopper!” I shouted.
The cabin door swung open and Molly belly-crawled onto the deck until she could see me. “Who started shooting at us?”
“Bad guys!” I cringed as another round hit the side of the boat and peppered me with wooden splinters. “Obviously!”
“Can we outrun them?”
“Not happening,” I said. “Ideas?”
“I could veil us?”
“Going to be hard to hide the boat’s wake, isn’t it?”
“Oh. Right. What do we do?”
“I need mist,” I said. “A bunch of it. Gimme.”
“Oh, ow, I don’t know Harry. I’d have to move an awful lot of fire to give you even a little. You know that’s not my thing.”
“It doesn’t have to be real mist,” I said.
“Oh!” Molly called. “That is exactly my thing!”
“Attagirl!”
“Fuck!” Thomas snarled. I looked up to see him stagger, holding on to the boat’s wheel with his right hand, his face twisted in pain. He’d taken a bullet in his left arm, just above the elbow, and he held it clenched in tight against his body, teeth bared. Slightly too pale blood trickled down his elbow and dribbled to the deck. “Plan B, Harry! Where the hell is plan B?!”
“Go, go, go!” I told Molly.
My apprentice closed her eyes and clenched her fists. I saw her focus, felt the slight stirring in the air as she gathered her will and power. Then she moved her hands in a complicated little gesture, whispering something. She continued making the gesture, and I realized that the motion was duplicating that of weaving three lines into a braid.
From between her fingers a thick white mist began to appear. First it came as a trickle, but as I watched it thickened to a stream. Then Molly bowed her head in concentration and muttered words beneath her breath, and a sudden plume of white mist bigger than the Water Beetle itself began jetting from her hands and spreading out to blanket the surface of the water over the boat’s wake, shutting the pursuing Sidhe away from view.
For a long minute we raced across the water, a wall of white mist spreading out to cover our wake. The enemy fire continued for a few seconds, but then dropped off to nothing. Hell, if we could keep this up, maybe we could make it back to shore without doing anything more. I checked Molly. Her face was pale, twisted into a grimace of concentration, and already the plume of illusory mist was beginning to wane. Mist isn’t a hard illusion to pull off, and it’s usually the first thing an apprentice learns to do with that kind of magic, but Molly was spreading the illusion out over an enormous area, and brute-force approaches were not her strong point in magic. We wouldn’t make it back to shore that way.
Fine, then.
“Thomas!” I shouted. “Throttle down! Let them catch up to us and then gun it!”
Thomas slowed the boat abruptly, and the sound of screaming Jet Ski engines rose up over the Water Beetle’s motor, growing higher-pitched as they approached.
“Molly, drop it on my signal!”
“’Kay,” she gasped.
My brother stood at the wheel with his eyes closed, focused intently on the sound. Then, abruptly, he gunned the Water Beetle’s engines again.
“Molly, now!”
Molly let out a groan and the illusionary cloud of white mist vanished as if it had never existed.
The formation of oncoming Jet Skis was only about fifty yards away, charging hard after us over the water, and they were moving so much more swiftly than us that within seconds they were almost on top of the Water Beetle. Jet Skis started swerving left and right to avoid a collision with our boat.

Cold Days Chapter 18, Page 178-180


“Come on,” I said, stretching out my legs. There was room. “It was at least an hour. How you doing back there, Molly?”
From the backseat, Molly snored. I smiled. The grasshopper had shambled to the truck and flung herself down on the backseat without saying a word.
“She okay?” Thomas asked.
“She pushed it today,” I said.
“With that mist thing? She does illusions all the time, I thought.”
“Dude,” I said. “It was hundreds of yards long and hundreds of yards across. That’s a huge freaking image to project, especially over water.”
“Because water grounds out magic?” Thomas asked.
“Exactly right,” I said. “And be glad it does, or the Sidhe would have been chucking lightning bolts at us instead of bullets. Molly had to sustain her image while the energy from which it was made kept on draining away. And then she hexed one of the Jet Skis. For her, that’s some serious heavy lifting. She’s tired.”
He frowned. “Like that time you collapsed at my dad’s place?”
“More or less,” I said. “Molly’s still relatively new at this. The first few times you hit your wall, it just about knocks you out. She’ll be fine.”

Cold Days Chapter 19, Page 183