You could read about Balerion the Dread.
Game of Thrones Season 3, Episode 10
Balerion the Dread.
Game of Thrones Season 7, Episode 2
But in the beginning, when it was home
to Balerion the Dread,
Game of Thrones Season 7, Episode 7
forged in the fiery breath
of Balerion the Dread.
Game of Thrones Season 3, Episode 6
you feeling such DREAD
at the prospect of me getting what I want.
Game of Thrones Season 3, Episode 6