Shrykos was a dragon, apparently female, associated with Prince Jaehaerys Targaryen.
Shortly after the birth of the twins Jaehaerys and Jaehaera Targaryen in the year 123, two dragon eggs were placed in their cradles. Two dragons soon emerged and Shrykos became associated with Jaehaerys.
At the beginning of the war of succession known as the Dance of the Dragons in the year 129, Jaehaerys Targaryen is already associated with Shrykos, but the dragoness is still too frail to be mounted.
Jaehaerys is murdered by Blood and Cheese before he can become a dragonrider. Shrykos remains in Fossedragon.
During the sack of Fossedragon in 130, the Shepherd's lambs manage to break through the lower gates into Fossedragon. Bound by heavy chains and unable to fly, Shrykos and the other dragons fight the mob with horns, claws and teeth, their breath turning the place into a fiery inferno.
According to the chronicle of the septon Eustace, Shrykos was the first to succumb, when a woodcutter known as Hobb the Chopper jumped on her back and plunged his axe into her skull.
Despite his jolts and roars, Shrykos is unable to dislodge Hobb, who clutches his blow with his legs: the woodcutter would then strike him seven times, bellowing the name of the Seven. The last one, the Stranger's blow, would have gone through the skull and hit the dragoness' brain.
The head of Shrykos and those of the other dragons who died that day are planted on posts inside the ruins of Fossedragon. Every night during the Three Kings Moon, the Shepherd appears near them to harangue the crowd with his apocalyptic preaching.
When Lord Borros Baratheon comes to arrest the preacher, the heads are in an advanced state of putrefaction. On the last day of the year 130, the Shepherd is tied to a post, surrounded by the heads of the five dead dragons, and King Aegon II Targaryen sets his body on fire himself.