He/She seems to have a personality of it's own.
It corrupts you. আপনি want it even if আপনি don't know why.
This is best shown in the beginning of Return of the King, when Smeagul and his cousin became immediately hostile towards each other..

The way Boromir describes it to the Council of Elrond. Despite inspiring one of the most classic memes..

The shot from the prologue of the men who will become the Nazgul, each holding a ring and standing in almost robotic uniformity, in contrast to the natural movements of the elves and the dwarves in the পূর্ববর্তি shots. And then the scene just fades as the darkness swallows them..

The Dead Marshes... আরো perfically the underwater scene.. That scene fucked me up as a kid..

Peter Jackson is an arachnophobe, and he used this to full effect to make the scenes with Shelob as frightening as possible. The part that was especially creepy was where she was following Frodo silently from above..