He nodded abruptly, and his knife disappeared back into his sleeve.
Spencer saw the knife disappear into the column of smoke that was Remo.
"I've changed my mind," she said, her own knife disappearing into her dark clothing.
They argue some more and then notice the knife has disappeared.
The knife, after a brief flurry that looked like a simple habit rather than showing off, disappeared as rapidly.
She relaxed her battle stance, and the knife disappeared into whatever hiding place she'd retrieved it from.
The knife made a great curve in the air and disappeared over the mountainside!
By that time, the black-haired girl had made the knives disappear again.
The knife went flying and disappeared in the grass.
The slim knife disappeared as quickly as it had sprung to his hand.