Gargish Silver Horn

The Gargish Silver Horn is an instrument used by the Gargoyle people to summon  silver serpents for ritual use. It appears in  Ultima VI and  Ultima VII.

Description
The great silver serpents that roamed the Realm of the Gargoyles were on occasion used by Gargish warriors to strengthen themselves before battle, with war parties seeking out and slaying such creatures before partaking of their venom—which sent them into a berserker-like rage. Presumably, the silver horn played a role in such undertakings, serving to lure the beast to the location of the company that sought to harvest its poison. The Avatar did have the option to blow into the horn to battle these huge serpents as well.

During the time of the Avatar's adventures regarding the Black Gate, such a silver horn had come to be housed in the Royal Museum of Britain, as part of an ongoing exhibit of artifacts revolving around the quests of the Avatar. Fortunately, when sounded within Britannia's capital at this point in time, no silver serpents appeared in answer to its call.

Trivia

 * Actually using the horn and then using magic spells like Kill to get rid of the serpents is a surprisingly good and relatively safe way to level-grind the Avatar.