Seasmoke was a pale silver-grey dragon, the pride and passion of Ser Laenor Velaryon, who had bonded with him by 101 AC. He was of fighting size by the Dance of the Dragons yet still young, twice the bulk of Tessarion and nimbler in the air than his elders. After Laenor's death in 120 AC he made his lair in the Dragonmont and went riderless for near a decade, until Prince Jacaerys Velaryon called for dragonseeds in 129 AC; Seasmoke killed Ser Steffon Darklyn of the Queensguard before Addam of Hull, fifteen years old, mounted him, and Addam used the dragon to shield his brother Alyn from Sheepstealer.
Seasmoke fought in the Battle in the Gullet and flew at the fall of King's Landing, and was kept in the Dragonpit to guard the city. When Queen Rhaenyra, fearing another turncloak after the Two Betrayers, ordered Ser Addam arrested, he was warned in time and escaped upon Seasmoke, taking the loyalty of the Queen's Hand, Lord Corlys, with him. Addam fell upon the green host at Tumbleton by night in 130 AC to prove that a bastard need not be a traitor. Seasmoke dueled the riderless Tessarion in the air and then, to spare the men below, flew at Vermithor; the Bronze Fury locked his jaws in the younger dragon's neck and tore his head away, and died of his own wounds moments after. The bones of the two dragons drew visitors to the rebuilt town for years.