This is a description of Gaelithox / Sheepstealer as how I have imagined him to be, now, of course, HotD will have its version of the Brown mutton lover but this is mine.
I have always considered Gaelithox to be rather similar to Smaug from the LotR universe (in size and shape), especially to the one in the movies (voiced by Benedict Cumberbatch) with a bunch of major differences.
Instead of being red and golden like Smaug, Gaelithox has mud brown scales with a far stronger underbelly that DOES NOT have a weak spot.
Smaug had greed for gold while Gaelithox has greed for sheep. Though admittedly he has not committed genocide over that.
They both have slender and long necks, though not as long and serpentine as Caraxes which have wing membranes on their hind legs to help in getting a lift from the ground.
While Smaug is arrogant, cruel, and vain, Gaelithox is relatively timid and vain, relatively being the key word. As long as you don't provoke him he will leave you alone.
And if you do provoke him, he will show his violent and vicious side which is something that the Dragonkeepers can attest to as will his OTL victims during the Sowing of the Seeds.
In other words, he is a sullen and moody bastard who is best left alone with his mutton.
Gaelithox does have more spikes and horns throughout his body compared to Smaug with his teeth being more sharper and pronounced compared to Smaug's relatively humanoid teeth.
The one major thing that these two have in common is that they have both attacked human settlements causing untold devastation and destruction that will forever be etched in the minds of men.
Though one attack was successful because of the presence of another dragon while the other was a pyrrhic victory for the humans.
The Desolation of Myr, the Rape of Myr, the Burning of Myr, and plenty of other names have been given to what Daemon and I did to Myr, while the Maesters have settled for Desolation, it has given Gaelithox a level of infamy in the same tier as that of Balerion and Vhagar.
Infamy on par with Smaug.
With all the fighting happening in the Stepstones, Gaelithox will soon become a war veteran like Vhagar and like Vhagar and Caraxes he will be a game changer during the Dance. Being in the same weight category as Caraxes and Meleys means that he will be devastating in my hands in the war.
After all, an experienced dragon with an experienced dragon rider is worth armies and is thrice as dangerous to an inexperienced rider regardless of the dragon