The Pink Runestone of Planar Warding is one of eight runestones created by an archwizard to seal away a dread demon from the material plane. Each runestone has a unique color and a unique magical affinity, Pink being the runestone of Illusions. Unlike the rest of the runestones, the Illusion Runestone is a semi-sentient item which knows that when united, the eight runestones can be used to re-summon the dread demon, and therefore actively tries to be lost and hidden by any who possess it.

As a GM, consider how the Runestone might try to tamper with the journey of those who possess it but making them go through mazes, entire conversations with characters who are not actually present, present days as nights or otherwise, as the Runestone desires to be lost and forgotten.