This one is actually many things.
1200 years ago there was a Dwarf named Urist Oharnan, who was known to all as Gregor for some reason. He was extremely wealthy and a great inventor and wizard. He built a giant metal horse and then brought it to life with magic. This horse was the size of an elephant, had horns, a poison stinger on the end of it’s tail and is rumored to have been able to project your parents disappointment from it’s eyes. This horse was used to guard his daughter from her many suitors.
At some point in time later a young dwarf wizard inventor created the Orphan Orb, this amplified his orphan status and made him immune to the horse’s eye rays. He also made a giant metal unicorn with which he challenged the horse for the daughter’s hand in marriage.
The ensuing battle, which ended in a draw, leveled 3 popular restaurants, a distillery and ruined the annual cheese festival. During this time, one of the horns was embedded in the leg of a beloved dwarf statue used for the bare foot cheese stomp, which was for some reason made of solid granite. They were unable to pry it loose so it had to be cut off.
Afterward the metal horse, whose name was Rockwell, was given to the manager of the cheese festival in the settlement for damages. He used it to guard his secret family recipe for blu goo cheese potatoes for the next 350 years. This continued until his grandson’s wedding, when a jilted lover proclaimed to all that the secret ingredient was asparagus. After this the horse was sold to the military, where it was used to great effect during a war with a marauding horde of orcs. However during a fateful battle the horse was damaged and went completely wild. It rampaged through the mountains and plains for many years until it was destroyed by a warrior, who was coincidentally named Gregor, that no one cares about, as he had been cursed to never receive recognition for any of his heroic deeds, of which he had many for his time. After this he melted down the horse into instruments and his party became a very successful 5 piece brass band of musicians. Gregor himself played the tuba.
The horn embedded in the statue’s leg remained there for 700 years. A dragon, who was believed to be lactose intolerant, attacked the cheese festival. During the attack a magical accident occurred and wild magic was unleashed. The statue and horn, melted by dragon fire and blasted with otherworldly magical energies reacted to create the second Gregor’s Horn, which was known as Gregor’s Golden Horn, even though it was silver and a guitar, due to a colloquialism of the time. This item caused anyone that heard it to crave cheese. It was obtained by a cheese merchant of questionable ethics, and after his attempts to use it to increase his sales destroyed a civilization, the Horn was hidden away in a vault whose location has thankfully been lost to time. With hope the world will never see ravaging hordes of cheese zombies again.
The young dwarf inventor ultimately won the hand of Urist/Gregor’s daughter and went on to great fame. However later financial problems led him to sell his metal unicorn as a floor piece/advertiser/ salesman for Hatfield’s Haberdashers, a successful chain of hat shops, and he has since become their mascot. It is known as Happy Hattie, the dappercorn.
The third Gregor’s Horn has nothing to do with any of the others.
There was a young boy named Gregory who lived in a remote village nessled between two mountains. He was often picked on even though he worked very hard to be taken serioulsy. One thing he wanted most of all was to be called Gregor, but everyone just laughed and called him Gregory. One day he found some old ruins and inside was a enormous horn which blasted the users words at enormous volume. Positioning himself outside the town, he screamed, “My name is Gregor!”. The corridor between the mountains amplified the blast, shattering the ear drums and leaving the town in ruins. He was beaten to death and the horn destroyed, but no one ever dare call him Gregory ever again.
Afterwards the horn was reforged into a helmet. It is in the possession of an orc mercenary/bandit currently wanted by the Fuczol authorities.
Appearance – A Blue metal helm with a large upward curved horn in the forehead.
Powers – This helmet, known as Gregor’s Horn, gives the wearer +10 to any saves vs deafening effects or anything that impairs his hearing, +10 to perception for hearing, does not take sleep penalites to hearing based perception dc’s, and grants 15 sonic resistance.
The fourth Gregor’s Horn is mentioned in texts 2000 years ago, but there is no other information available.