Mind Fog description

The store lights went out, all at once.
My heart all but stopped. A second later, battery-powered emergency lights came up and revealed a roiling cloud of silver-grey mist spreading into the store from the doors. The mist rolled over a startled cashier, and the woman slumped, her mouth slightly open and her eyes unfocused, staring.
"Good Lord," Murphy said softly. "Harry, what's happening?"
I had already gotten out of the booth and grabbed the salt shaker from our table, and the one next to it. "Trouble. Come with me."

Summer Knight, Page 222


At first I tried to circle around to the exit doors, but the mist proved to be flowing in through them as well. "Curse it! We can't get out that way."
Murphy's face went more pale as a young man flung himself at the exit doors. The moment he hit the mist, his running steps faltered. He came to a halt, a puzzled expression on his face, and stared around him blankly, as his shoulders slumped.
"Dear God," she whispered. "Harry, what is that?"
"Come on, to the back of the store," I said, and started running that way. "I think it's a mind fog."
"You think?"
I scowled over my shoulder at Murphy. "I've never seen one before, just heard about them. They shut down your head, flatline your ability to remember things, scramble your thoughts. They're illegal."
"Illegal?" Murphy yelled. "Says who?"
"Says the Laws of Magic," I muttered.
"You didn't say anything about any Laws of Magic," Murphy said.
"If we get out of here alive, I'll explain it to you sometime." We ran down a long aisle toward the back of the store, passing housewares, then seasonal goods on our left, while grocery aisles stretched out on our right. Murphy stopped abruptly, broke open the covering over a fire alarm, and jerked it down.
I looked around hopefully, but nothing happened.
"Damn," Murphy muttered.
"Worth a try. Look, the people in the fog should be all right once it's gone, and whoever this is, they won't have any reason to hurt them once we're not around. We'll get out the back door and get away from here."

Summer Knight, Page 224-225