Spike's eyes were clamped down tight over his dream, his teeth bared at the image before him, and he thrashed around in his bed. Low growls escaped his throat, and Twilight Sparkle took a step back; she was terrified. She had tried to reach into his mind, to calm his dreams, but what she had seen there... It was taking much of her will not to run away in panic, and that was even knowing that the thing was merely a dream.
Spike's claws imbedded themselves into the floor, and as he clenched his fist he left the wood scarred. Had he been awake, Twilight was certain the sound that issued from his throat would have been a scream. His leg kicked out at a dream-phantom, and her bed broke.
"S-Spike?" she stammered, flinching as a cloud of smoke issued from his nostrils toward her. "Spike, w-wake up!"
There was no indication that he heard her. The image in her head faded enough that she began to act rationally again, containing his next exhalation of flame in a magic shield where it quickly burned itself out. His face was contorted in pain, and she grasped him in her spell and shook him. "Spike!" she yelled. "You need to wake up!"
Something went wrong. Held in her magical grasp he made that noise again, and something pulsed against her magic. She gasped and took a reflexive step back as she felt something dark brush her mind—
"Pitiful little pony," a voice purred. "You believe you can save him, that he cares for you." The voice chuckled. "You have no hold over him."
Twilight tried to turn, to confront this strange presence in the darkness, but found herself unable to move. Instead, she simply spoke, and was surprized to find her voice was steady. "Who are you? What do you think you know about us?"
"I know you treat this dragon as a slave," the voice whispered. "I know he hates you for it."
"You're wrong! Spike is like a brother to me, and I would never mistreat him like that! We're family!"
Her shout echoed in the dark, but only silence followed it. Twilight could hear a drum, but soon realized it was only her own heart. She still couldn't move, but as she tried to slow her breathing she heard a quiet laugh. Soon, it echoed loudly all around her.
"Foalish little creature," the voice said, and the laughter didn't stop. "If he truly loved you, then why does he betray you?"
"He would never," Twilight whispered.
"He already has."
—and suddenly the room was awash in a flickering green glow. The smell of woodsmoke stained her nostrils, and she quickly realized that the green light was Spike's fire; the library was burning. She brought her hoof up to her mouth as she was suddenly racked by coughs. Then, through the smoke and emerald haze, she saw him. He was standing now, his eyes open and his arms hanging almost to the floor as he hunched forward. His eyes shone in an unnatural green light, and through his smile wisps of smoke and fire seeped out.
A low growl slipped out from between his teeth, ending in a hiss. His wings stretched and flared out, catching the light of the fire in the emerald leather. Green against green. He dropped to all fours, then leapt into the night sky.
She saw him flap once in the moonlight, then he was gone. Around her, the library burned.