Smaug was already terrible in the days before he took Erebor and razed Dale to a smoking hollow ruin, though none so many knew his name. To those poor North-Folk whose treasures caught his eye, he was known only as a great shadow in the sky — Death, come to claim his due — and they fell all screaming as they burned.
But tonight… tonight he ached in his mind, for all the towns and cities and villages and hamlets in the area surrounding the cave he'd claimed to collect his hoard had been relieved of whatever meager baubles they'd had as offering to his greed. So he flew far, jealousy for what he already possessed matched and outweighed by his need for more. North and norther still he carried on till the sky to the east lit grey with the first guess of dawn, over forests and mountains higher and higher and rivers quicker and stronger, 'til across a small sea toward a sparsely treed coastline.
It was there, in that far land, and then, as he flew over and among cliffs and copses, that something reflective caught his eye. His eyes gleamed with interest and he dropped low to land and weave between the trees. Drawing near, he saw the thing: A shining mirror of beaten silver framed by copper wrought so skillfully the trout pictured there seemed truly to leap and race.
And from another way, a she-drake with scales of deepest blue approached, entranced.
A snarl grated in Smaug's throat and he leapt upon her, tumbling her easily with his greater size and strength. A great whuff of breath left her as she slammed to the ground, but she recovered quickly, baring her dagger-sharp teeth, scraping claws against his scales and kicking powerfully at his exposed belly as she flapped her wings at his face.
"You — Egg-bearer!" he roared, swatting her wings away with his own and trying to roll her to her side so he might pin her limbs, his tones pitching into mania. "You dare lay eyes on what I've claimed?"
She snapped viciously at his throat and gave an especially mighty kick.
"Enough!"
The cry rang in his mind clear as if he'd felt the sound of it and stunned him just long enough the she-drake could squirm from underneath him.
She regained her feet quickly, posturing boldly before the bigger dragon with wings flared out and neck arched forward.
"You, limbed-snake," the thought came scathingly, in no voice he'd ever heard, "winged-lizard, disgrace your kind, whatever they may be."
His eyes lit at the mockery, his lips peeled away from his fangs, a growl and fire in his breast. "You speak to my mind, Blue-Bird. Did you once so wag your tongue that it fell out?"
A hissing snarl, narrowed eyes, and a shudder of wings was his first answer. "Did you never learn to share a thought without the roar of a beast?"
The horns of his crest flared and he opened his mouth to bellow a retort, rearing to tower over the insolent hatchling, when a cry came from near the mirror — his mirror — and a blinding flash struck him across the snout. He shouted, shaking the glare from his eyes before turning a furious gaze upon the newcomer.
It was black as night with moss-green eyes that scowled from beneath lowered brows. Like the female, it held its wings wide, but held its head low, baring short ivory teeth at the intruders. And it was young, not even having seen the better part of a century, though not so young as the she-drake.
"Oh, another to try at me?" He grinned as the black dragon hissed. "Tell me then, wyrmling, how you may best meet your end."
Smaug lunged forward, but a sudden blaze of blue lit along the little beast's spine, and another fiery shot struck him full in the face. A roar rang out through the woods, shuddering the air, and shivering to Smaug's bones, and even before he knew it himself, both his and the she-drake's proud heads were hung low before this speechless creature.
A/N: Done for a prompt over on Tumblr. "Smaug and Saphira both discover a treasure at the same time - guarded by Toothless". I love crossovers and I love dragons and I had way too much fun writing this.