Grey Ghost
A shy, white-grey wild dragon that fished the sea around Dragonstone and avoided people entirely.
The beast itself
Grey Ghost was a pale whitish-grey, very nearly the colour of the steam that comes off the vents of the Dragonmont, and the name is a description rather than a flourish: against that mountain, in that weather, he was genuinely hard to see. Even people who lived on Dragonstone their whole lives could go years without a proper look at him, and the accounts of his size vary wildly for exactly that reason. He was somewhere between middling and large, long-winged, and a strong flier over water.
He fished. That is the extraordinary thing about him and it is worth stating plainly: an animal capable of burning a village chose instead to hunt the sea, taking fish off the surface in long low passes and swallowing them on the wing, day after day, for years. He kept to the smoking vents on the seaward side of the mountain, roosted alone, and avoided everything ÔÇö men, ships, flocks, and above all other dragons. He was skittish to a degree that no other beast in this collection approaches: a single boat coming around the headland was enough to put him in the air and out over deep water. He was never heard to roar. Several chroniclers doubted he could.
Those who tried to claim him
Grey Ghost was on the list when the blacks went looking for riders, and the attempts on him failed in a way that was almost comic rather than tragic. Nobody was burned. Nobody was eaten. The volunteers simply could not get near him: he heard them coming up the seaward slope, went off his ledge without a sound, and spent the rest of the day out over the water where no man on foot could follow.
That happened often enough that the dragonkeepers gave up on him and struck him off, and the war moved on to beasts that would at least stay still long enough to be attempted. For a while there was a running joke on Dragonstone about the dragon who could not be claimed because he would not be present.
What the smallfolk of Dragonstone said
The fisherfolk of the island knew him better than the castle did, because they were the only people who saw him regularly, and they were quietly fond of him. He took fish they could spare from a sea they thought inexhaustible, he had never harmed a boat, and he had the good manners to keep away. Some of them left him offerings on the rocks in bad weather, which was harmless and which the septons disliked.
There was a superstition attached, as there always is. Sailors held that a glimpse of the pale dragon on a crossing meant clear water ahead, and that he could be seen most often just before the weather turned kind. The maesters at the castle wrote nothing about him at all worth keeping, which tells you something about what the histories consider a dragon to be for.
What became of it ÔÇö if an ending is written, it is here. Spoilers.
Grey Ghost was found torn in half. The Cannibal was blamed. Being uninvolved turned out not to be a survivable position for a dragon in those years either.