Disclaimer: I don't own Winx Club.
The Trix stormed into Cloud Tower, more or less literally.
"Selina!" Icy barked out. Her tone of voice indicated that she was not pleased. "Selina!"
"Yes?" Selina stepped out from a hallway, into Cloud Tower's entrance chamber.
"Your monsters failed." Icy spat contemptuously, each word an icicle of anger. "Again."
"The Winx destroyed them with ease." Darcy said. "If that book is as powerful as you claim, surely it must have stronger monsters within its pages."
"Yeah!" Stormy exclaimed. "Give us something stronger! Something... Bigger! Give us the biggest monster you've got!"
"The biggest...?" Selina trailed off. "I don't think..."
"What are you, afraid?" Icy demanded. "Do it!"
"If you're sure." Selina opened the Legendarium, turning to a page covered in intricate artwork and powerful magical symbols. She held the book open and began to speak.
"From the depths of time, from histories lost, I summon the great beast, the Destroyer of Vecca, greatest of her children, foulest of them all, I summon the Dragon King, Koroboras!"
Far away in a cloud of boulders floating in empty space, a form stirred. It opened its jaws in a soundless roar. A portal opened in front of the creature, which slipped through.
"Dragon King?" Icy asked, pleased. "Sounds promising."
"I bet he's as big as Alfea!" Stormy said, practically bouncing with excitement. "When do we get to see him?
"Now." Selina said.
Thunder shook Cloud Tower as a black gateway opened in the sky. It blocked out the sun, covering Cloud Tower, Alfea, and Magix in shadow. Through it, a massive creature emerged. First came the jaws, large enough to consume an entire castle with a single bite. The rest of the head followed. Horns the size of Cloud Tower jutted from the beast's forehead and his massive eyes surveyed the land. A layer of thick interlocking scales covered his skin, giving him nigh impenetrable armor. A huge clawed foot emerged, large enough to obliterate Alfea with a single step, followed by an equally massive leg. His first step in the realm of Magix crushed half of Black Mud Swamp, and the rest of him soon followed; massive wings as wide as his body was long, spikes the size of trees running down his back, and a tail that whipped around with terrifying speed.
Koroboras had emerged.
"Uh, Vecca was a city, right?" Darcy asked, suddenly nervous. She hadn't expected something quite this big.
"No." Selina replied. "It was a planet."
"A planet?!" Icy screeched. "We want the Winx dead, not the planet destroyed!"
"You said you wanted the biggest monster in the Legendarium." Selina said. "This is it."
"How are we supposed to control him?" Icy demanded.
"You're not." Selina said. "Not even Bloom can stop this monster, let alone control it."
"Great." Darcy said. "Just great. I don't suppose you know how to get rid of him?"
"Last time it took the unified effort of five planets to do it."
"You've got to be kidding." Stormy said. "Five planets? How is anything that strong?"
"He ate an entire planet and absorbed its magic in the process."
"Right." Icy said. "Sisters, I think we can leave Koroboras to his work. Let's go." They vanished, taking Cloud Tower with them.
The Winx sat in the quad at Alfea, resting up after their last fight with the Trix and their pet monsters. A shadow fell over them. Bloom looked up and her heart crawled into her throat. "Girls..." She said carefully, "I think we have a problem."
Koroboras roared. The ground shook. Every window in Alfea and in Magix shattered.
"A big problem." Bloom said in a breathless whisper.