And behind the mountain dwelled three wild dragons, never claimed nor ridden by any man, living or dead. The smallfolk had named them Sheepstealer, Grey Ghost, and the Cannibal.

- Fire and Blood "The Dying of the Dragons: The Blacks and the Greens"

A man called Silver Denys, whose hair and eyes lent credence to his claim to be descended from a bastard son of Maegor the Cruel, had an arm torn off by Sheepstealer. As his sons struggled to staunch the wound, the Cannibal descended on them, drove off Sheepstealer, and devoured father and sons alike.

- Fire and Blood "The Dying of the Dragons: The Red Dragon and the Gold"

Dragonstone’s three wild dragons were less easily claimed than those that had known previous riders, yet attempts were made upon them all the same. Sheepstealer, a notably ugly “mud brown” dragon hatched when the Old King was still young, had a taste for mutton, swooping down on shepherd’s flocks from Driftmark to the Wendwater. He seldom harmed the shepherds, unless they attempted to interfere with him, but had been known to devour the occasional sheep dog.

- Fire and Blood "The Dying of the Dragons: The Red Dragon and the Gold"

Sheepstealer proved easier to flush out, but he remained a vicious, ill-tempered beast, who killed more seeds than the three castle dragons together.

- Fire and Blood "The Dying of the Dragons: The Red Dragon and the Gold"