Dragonspider

Ancient Dragon and Spider Queen. In the black depths of the Underground Lair, where the stone whispers ancient curses and the air is thick with rotting cobwebs they clashed. Spider silk against dragon fire, fangs against claws. The Queen was as swift as death, her venom dripping onto the rocks, leaving smoking pits. But the Dragon was ancient, his mind cold and merciless. He broke her legs one by one, tore at the webs with his fangs, until at last he caught her in his mouth and swallowed her whole. But the Spider Queen did not die.
Her flesh, steeped in ancient magic, was not digested. Instead, it began to digest him from the inside.
Days later, the Dragon had changed.
His skin split, and new limbs emerged from the cracks - long, hairy, with hooks at the ends. His wings were covered in a pattern of webs, and from his mouth now flowed not only fire, but also sticky silk. On his back, humps bulged, from which grew additional eyes - shimmering, numerous, like the Queen's.
His mind was no longer his own.
Now both lived in him.
The Dragon and the Spider.
A single monster.