Did Gollum Frighten Sauron?

In 3017 of the Third Age, Gollum was captured and tortured by Sauron in Barad-dûr. Despite the Shadow of Fear—the power that had broken kings and created the Nazgûl—Sauron perceived something indomitable in this wretched creature that could not be overcome except by death. The paradox lies in Gollum's complete corruption: five centuries of Ring addiction had consumed his entire identity, leaving nothing for Sauron to threaten or manipulate. Gollum even lied under torture, misdirecting Sauron about the Shire's location. Sauron's binary worldview—seeing only dominated slaves or power-seeking rivals—could not categorize this third state of pathological obsession. He released Gollum, hoping to use his malice to track the Ring, a fatal miscalculation. This reveals evil's ontological blindness: corruption cannot comprehend what it has destroyed within itself. Ultimately, the mercy Bilbo and Frodo showed Gollum created the conditions for eucatastrophe at Mount Doom, where Gollum's indomitable obsession destroyed the Ring when Frodo could not.