Today, this Monster is a literal ton of hairy muscle and claws, but once upon a time it was a younger nephew thrice removed of Kamu the Mighty. Kamu was notorious for finding inventive ways to dispose of his family and this young man wasn’t having any part of it. After losing five siblings to an enchanted cow sent by Kamu which laid explosive cursed cow-patties throughout the family villa, the nephew decided to go into deep cover. He went into the family sorcerer’s laboratory and drank everything on the shelf. The mixture of potions and random magical ingredients caused a variety of unfortunate side effects which initially made the hapless fellow wish he’d started with the section marked “Poisons, I think.” (The sorcerer was not one of the most organized.) However, after an exciting twenty minutes of colored smoke, swirling magical energies, and extremely noxious emissions, the boy’s transformation was complete and he became one of the most feared creatures in all the land. Duke Eekrah the Nasty paid the sorcerer handsomely for years to try to recreate the accident, but eventually lost patience when it became clear that the sorcerer had a better chance of turning cowpatties into gold than he did creating more Horrible Monsters, and Eekrah fed the hapless wizard to the Killer Wolf Frogs.
The Hairy Monster is generally presumed to have the mind of a beast, although a Legionnaire who took a wrong turn and ended up in the Monster’s lair reportedly found neatly folded stacks of the Times, with the crosswords all done in ink no less.