Krakanrok the Black

Krakanrok the Black is the Father of the Dragon Ogre race. He is an enormous mountain-sized Shaggoth of terrible power.

Overview
Krakanrok the Black is the largest and oldest of all his kind. Quite literally the size of a mountain, Krakanrok slumbers upon the Chimera Plateau in the Chaos Wastes.[1a] During Archaon's quest for the Slayer of Kings, he ascended what he thought was a mountain, only to discover it was the sleeping form of the sire of the Dragon Ogres. The strongest of Archaon's champions managed to lift a single one of Krakanrok's mighty claws, and Archaon pried free the sword. The Everchosen killed his own champion to sate the screaming of the Slayer of Kings, not willing to risk waking the ancient terror.[1b] It is said that during the End Times there will be an enormous thunderstorm which will cause Krakanrok to awaken.[1a]

Trivia
It is unconfirmed whether Krakanrok is any related to Kalgalanos the Black. In addition to having the same title, both are Fathers of Dragon or Dragon Ogres, as well as being colossal in size, and currently sleeping deep beneath the earth. If they are related, it's possible their names are synonymous of the same creature, their legends diluting the truth over the long centuries.

Source

 * Warhammer Armies: Warriors of Chaos (8th Edition) -- pg. 41, 20