Kill him.
Obito was horrified. "Kill...Kakashi?" He asked unsteadily, inching up slowly away from the mirror. The evil grin the dog sported made him feel like puking.
"Wh-why?"
The dog made a sort of growlish sigh. Then, almost like water, the mirror rippled and the humongous beast stepped lightly through.
You do understand that I'm a demon. Demons have no purpose for killing.
It seemed to consider a thought for a moment.
Besides, it continued, walking steadily towards Obito with maneuvered steps that left Obito immobilized with fear, I'm the one that kept you alive for three years. I'm the one that skipped eleven years through time to make sure you were long forgotten by most people.
It stopped, and washed a forepaw daintily with a slight reddish pink tongue.
Or, I could just do it myself. It said with a air of undecided finality.
"How?" Obito demanded, trying to sound brave.
The large white dog turned and leaped back through the mirror.
You'll see. I'll give you your voice, just as a reminder of what happened. Oh, and, don't mention any of this, okay?
The dog turned its shaggy head back towards Obito.
Your friend just might think you're delusional.
That was all Obito remembered, the ghoulish dog, the mist the mirror, and, oh, the painful feeling of being turned back into a wolf.
And then there was sunlight streaming in through the room from the half covered windows. Kakashi was opening the blinds, and didn't seem to notice Obito staring frightfully at him.
Remember...