The description matched the nail-filled vessel spotted at Redoubt 9, which is placed in the median of Interstate 64. The bottle functioned as a talisman, which was meant to keep away the evil spirits.
The Elder Scrolls Online’s Fallen Banners dungeon pack is coming this month, and the team is previewing one of the new dungeons, Exiled Redoubt (after previewing the other, Lep Seclusa).