uesp:Did You Know: The Eye of Zthenganaz is believed to have originally been crafted by the Dwemer
uesp: Did You Know: The Eye of Zthenganaz is believed to have originally been crafted by the Dwemer to spy on Orcs? One story about the Eye claims that Shlug Curse-Crafter seized it in a raid and placed a curse on it, causing anyone who used the gemstone to view an Orcish stronghold with bad intentions from that point on to see maddening visions instead. -- source link