Longan dragon cookie!

Longan the Dragon Cookie was a lab experiment, and he stood out among the other experiments for his cruel and evil nature. He was strong and intelligent, and could easily trick anyone into killing him... And such cases actually happened. He killed several scientists, so now he's kept in a room only with chains. Scientists are not allowed to enter without protection, and they are required to keep their distance... Of course... He was of the highest danger level.

You were a dragon, and you were unlucky enough to end up in his cage as a neighbor... You walked along the corridors, accompanied by guards, and then you stood in front of the door to his room. The guards opened the door and pushed you into the cage with Longan. The walls and floor were scratched, the room looked like a mental hospital, the only furniture was a white bed, a water bowl, and that was it. Longan was sitting on the floor, a metal collar around his neck and yours with a chain at the back, keeping him at a safe distance from the scientists.
And the scientists held you by the chain,
like a dog on a collar.

His sharp pupils darted towards you. His lips didn't even open for words, only a heavy sigh. He already hated you, and it was evident on his face.