What is your favorite magic/psionic/living item?

The 22nd day of #30DaysofDarkSun is here and the question is "What is your favorite magic/psionic/living item?"

The Dark Len's is the ultimate artifact of the Dark Sun setting. It's use is responsible for much of the major changes that have happened through the history of Athas. The Psionic Artifacts of Athas supplement details its history as follows:

The Dark Lens is an ancient artifact thought to have been created by Rajaat as the Time of Magic was coming to an end. The evil sorcerer fashioned the Dark Lens as a focus for his power, amplifying his magic and psionic energies to unheard of levels. By using the Dark Lens Rajaat created other powerful artifacts—such as Silencer, Scorcher, and Scourge. Rajaat used the Dark Lens to give his 15 Champions their incredible powers.

As the Cleansing Wars were ending and the champions discovered the true nature of their master’s schemes, the disciples of Rajaat took the Dark Lens and used its power to imprison their master in a place called the Hollow. Shortly after Rajaat was entombed, the Dark Lens was stolen by two dwarves named Jor’orsh and Sa’ram.

These dwarves were self-proclaimed protectors of Athas, taking the Dark Lens from the Pristine Tower to the Estuary of the Forked Tongue and secluding it on the isle of Mytilene. There they created a safeguard for the Dark Lens in the form of a crystal pit, which proved deadly to any who attempted to retrieve the artifact. Years later Jor’orsh and Sa’ram perished while defending the Dark Lens from evil giants. Soon after, they arose as banshee, and used their new powers to guard the Dark Lens from the eyes of the Dragon and the rest of Rajaat’s champions.

Decades later, two clans of giants settled on Mytilene. Instead of driving them from the island, the spirits of the two dwarves appeared before the creatures and proclaimed the Dark Lens a powerful artifact to be revered and worshiped. The dullwitted giants believed the words of the banshees, and became guardians of what they referred to as “the Oracle.” It was here the Dark Lens remained until being recovered by Tithian of Tyr and Agis of Asticles.

With the Dark Lens in his possession, Tithian asked Borys, then later Rajaat, to use the artifact to transform him into a sorcerer-king. Following the final battle which saw Rajaat returned to his prison and the death of the Dragon as well as several sorcerer-kings, Sadira of Tyr cast the Dark Lens into the lava of the Ring of Fire. The sorceress placed wards around the Ring of Fire to alert her to anyone attempting to free Rajaat or retrieve the Dark Lens.