Its a giant sized minotaur with 4 arms, 2 of which end in hands, the other 2 end in blades. it also has mouths all over it. Keeper fo secrets would make a great base for a conversion as its too big really to be a Minotaur.
The Ghorgon is a giant, mutant Minotaur with four arms, two of which usually end in scythe-like claws. It has some of the abilities of regular Minotaurs (like going mental when it gorges on flesh) and can also regenerate by eating. It’s much larger than a Minotaur - about the size of a Giant.
The thing that throws rocks is a Cygor, another mutant strain of Minotaur, but a bit more specialised. It has a single eye, and can only see the Winds of Magic, which makes it insane. It hates Wizards as these are the only living things it can truly see, so it hunts them down to the exclusion of all else. For this reason, Wizards are terrified of it. It hurls chunks of mehir from magical stone circles - again, some of the only things in the physical world it can perceive. Like the Ghorgon, it’s about the size of a Giant.