All the right moves

'Stiles...'

Derek almost choked on the name.

'Yeah?' Stiles said. 'What? Go on. Say whatever it is you were going to say.'

'I don't want to say it,' Derek admitted. Was there something about Stiles' eyes that was different? Were they darker? Colder? No, they weren't. They were exactly the same. Then why did Derek shiver when Stiles looked at him now?

'Who are you?' Derek asked. Stiles blinked, confused. One corner of his mouth curled up in a hesitant smile.

'I'm Stiles. I'm the kind, goofy, loyal guy everyone knows and loves,' Stiles answered. He turned his open, trusting face towards Derek. Same, same, same, Derek thought. Identical. Unchanged. Then why did Derek's flesh crawl?

'Except we don't, do we?' Derek replied. He was half-expecting Stiles to lie some more. To continue play-acting. They stared at each other. Stiles' face hardened.

'No. I can't fool you, huh?'

Was it a relief to have his suspicions confirmed? Derek didn't know. Stiles was something else, which meant Derek hadn't gone insane. He would have preferred the latter option, to be honest.

'You gave yourself away,' Derek growled.

'Don't lie, Derek. I didn't make a mistake. My performance was flawless. I didn't pretend to be that guy. I became him. Even when no one was looking I was a harmless dork. So, the question is: how did you know?'

Derek didn't answer. He didn't know why or how he'd known. He just knew. This thing – whatever it was – wasn't Stiles. It looked like Stiles and sounded like Stiles. Behaved like Stiles. Smelled like Stiles. Yet, it was wrong. Off. It didn't feel like Stiles. It felt other.

'I tricked the rest. They looked, but there was nothing to see. For some reason, though, you kept looking. You're always looking.'

Suddenly, a huge smile appeared on the thing's face. A cruel smile. It chuckled. Derek glowered at it; his claws at the ready.

'You're always looking,' the thing repeated. 'Because you like me. Because you love me?'

'We all love you. Except, again, we don't. 'Cause you're not Stiles,' Derek responded. He could tear this thing from limb to limb. Slit it open.

'But this is his body,' it cautioned. Reluctantly, Derek retracted his claws.

'What would you like to do with this body? No nails. No sharpness. Think soft and tender. Think Stiles. What would you like to do to Stiles?'

Derek closed his eyes. It was a stupid thing to do. The thing was probably waiting for an opportunity like this. Derek opened his eyes again. The thing regarded him with obvious fascination.

'Think about his eyes,' it persisted. 'How bright they are when he smiles. They're not regular brown; those eyes. Oh, I'm sure you've noticed. They're caramel and honey and amber and whiskey and gold. They're weirdly warm, aren't they?'

Derek didn't nod, but he might as well have. The thing winked.

'Think about the light dancing across his handsome face. What if that light was instead you, Derek? Think about touching Stiles where the light touches him. Your fingers skirting and sliding over Stiles like the sun. Think his skin underneath your fingertips. Isn't he the most beautiful thing you've ever seen?'

'Think this mouth. Not yapping away like usual. Lips slightly open, waiting for you to kiss them. To kiss him. Stiles. Can you taste him? Think his heart beating. So loudly that you'd hear it even if you were human.'

'Stop it,' Derek breathed. His protest rang false. The thing smirked.

'Think about Stiles,' it whispered. Like Derek needed any encouragement.

'Such a beautiful boy. So pretty. Don't you want to possess that beauty? Think his body under yours,' the thing urged. It didn't seem to be able to shut up.

'Think about laying your hands on him. Maybe he struggles a little. Maybe that sweetens the deal. Does it matter if he wants you too? Of course not. He's yours. You'll take him anyway,' it suggested. Derek's silence grew chilly. The thing cocked a curious eyebrow.

'Doesn't that excite you?' it asked. 'Imagine the fun of taking him by force. The thrill of it. Come on, repress your prudent side. Be who you really are. You are a predator. Fucking act like it. Rip apart that purity. Watch the blood pearl on his pale throat.'

'Enough!' Derek roared, attempting to seize the thing. It batted him away as if he was an annoying fly.

'Nice try,' the thing cackled. Shaken, Derek got to his feet. It was stronger than he'd expected. Not important. It was still going down.

'You think you know me so well. Prepare to get to know me better. There's nothing I won't do to bring Stiles back.'

The end.