Sherlock looked John in the eye.
"However. There is nothing we can do about my species right now, and I am STILL BORED! So, I am now- deleting- Laser pointers." His eyes unfocused for a moment. "What?" he asked, looking slightly amused at nothing.
"Er. If they don't have a case for you, why don't we go home? I've got, y'know, stuff to do," John suggested.
"Fine. Just let me slice Anderson to ribbons-" Sherlock protested with a squawk as John picked him up unceremoniously and carried him out of the office.
Everyone in the office looked relieved as Sherlock left.
"I'm glad that little demon's gone," Anderson said. "Did you see what he did to my hand?"
When they got back to the flat, John dropped Sherlock on the couch and went to make tea. There was silence for a few minutes.
"John. You realize this may be permanent."
John put down the mug he was holding and turned around. Sherlock was staring at him, somehow managing to wear the same expression he'd used as a human.
"I...I hadn't really considered the long-term," John admitted.
"So far, I don't see how I'm going to become human again," Sherlock said quietly. "People are going to ask all sorts of paranoid questions about my status as a person and animal rights and all that. You're going to have to help me fend them off. They won't want to listen to a cat."
John looked over at his flatmate. "No, they won't. Not at first. But you're still you! Still brilliant! I think they'll have to see that you're the same person, just... not quite human."
"Moriarty might 'convince' them otherwise."
John paused. "You think it's him, then."
"I can never rule out that possibility. He'd be the only one with the resources and connections to do this kind of thing. I've no idea how, for once- some kind of genetic manipulation or something equally complex, but I still think it's him."
"Jumping to such conclusions already, hmm?"
John and Sherlock turned towards the door. Sherlock hissed.
"Goodness, dear brother," Mycroft said, peering distastefully at the cat, "You've gotten yourself into quite a situation, haven't you?"
Sherlock jumped to the couch back and faced the wall.
"What happened, John?" Mycroft asked.
"I honestly have no idea. This morning, I woke up, came downstairs, and Sherlock was a cat."
"Just...a cat? No intruders in the night? No funny behavior over the past few days?"
John held up his hands. "Not as far as I know."
Mycroft turned his dear-brother-why-do-you-put-me-through-this-kind-of-thing glare towards Sherlock's back. "Any ideas?"
"I had eleven."
"In other words...?"
Sherlock growled. "In other words, I. Don't. Know."
A/N: Ah, chapter 4. Just so you know, this may be the last chapter for a bit while I figure out where this is going. I'm trying to figure out wether Moriarty is involved, or if it's magic, or if it's a cruel joke of Mycroft's. Reviews give me ideas!