Old warhorn

An old warhorn is one of the objects found by Samwell Tarly in the Fist of the First Men during the Great Ranging.

Season 2
The warhorn is found along with spear and arrow heads made of dragonglass, all wrapped in the black cloak of a brother of the Night's Watch.

In the books
In the A Song of Ice and Fire books, the warhorn and dragonglass caché is found by Jon Snow and Ghost and then given to Sam. The warhorn is made from an auroch's horn and is banded with bronze. On closer examination the horn had proved cracked, and even after Jon cleaned all the dirt out, he was unable to get any sound from it.