Help me name this creature?

“They say its head bears the skull of an ancient beast; a monstrous ram once revered by the Herdsmen clans. Whether the creature wears it as a grim trophy or it has somehow fused with its body, none can say. Travelers who glimpse the skull rising from the mist often mistake it for a forgotten altar or an ominous shrine. Only too late do they realise that it moves, that it hunts. Its back is drenched in the detritus of the swamp; a mane of stench and decay. Those who sink into the cold embrace of the bog often see this totem of despair in their final moments.” – Excerpt from ‘Hidden in the Mists’