Pegasus

Pegasus is the great white winged horse of legend. He is a handsome white horse, with beautiful wings of delicate white feathers. The leather bridle is around the winged horse's head.

Background
An Evil Enchanter in Kolyma had turned the horse into a viper after he had refused to be his steed. Graham broke the enchantment by returning the horse's Leather Bridle.

The horse then gave Graham a magic Sugar Cube in thanks. It then flew away. Pegasus has a very independent nature, and will not allow riders on his back.

Stone statues of Pegasus lie outside the Desert Temple in Serenia, and seem to guard the crumbling temple.

Behind the scenes
Though its name is not mentioned in KQ2, King's Questions and An Encyclopedia of Daventry confirmed that the horse is indeed Pegasus.

King Graham can pet the horse.

The winged horse statues in KQ5, are also referred to as Pegasus.

A winged horse like either Pegasus or Night Mare can be seen in inside the Castle of the Crown.

In the unofficial King's Quest II: Romancing the Stones, the Deciple of the Cloud was inspired by Pegasus.