Muu-chan is an unknown quantity. (meta-fic, meme response for feliciter.)
They were having tea -- or, rather, Kantarou was having tea, Haruka was continuing to sulk over Kantarou's rather unorthodox use of his bowl on their last job, and Youko was muttering over their finances -- when Sugino burst in through the window.
"Muu-chan! Muuuu-chaaan! Have you seen Muu-chan?" he demanded of the nonplussed company, then rounded on Kantarou. "Did you steal her again? Where is she?"
Sugino turned away for a moment to survey the room, and while their attention was focused on him, as if on cue, Muu-chan dropped into Kantarou's lap. Kantarou chuckled as she muu-ed into his ear. "She wouldn't have to keep running away to get a break from you if you didn't cling to her so much," he said.
"You did steal my Muu-chan!" Sugino accused, and snatched the small green youkai from Kantarou. "Eh, what's that?" A small, flat plate with a hole in the middle fell from Muu-chan's little hands, and Kantarou picked it up. They all craned to look at it.
It was a strange, hard plastic, one side almost ordinary, with foreign writing on it, and the other side with a peculiar metallic quality that broke into a changing rainbow of colours as Kantarou tilted it. Both the tengu were entranced. "Tactics disk 1," Kantarou read aloud, puzzled.
The disk refused to give up any secrets to their examination, and eventually found a place on Haruka's shelf with various other shiny objects.