Luxon Beacon

From Explorer's Guide to Wildemount, page 268.

Description
Wondrous item, legendary.

This dodecahedron of faintly glowing crystal is heavier than it appears. A set of handles are affixed to its sides, and it pulsates and thrums when touched.

Fragment of Possibility. A creature that touches the beacon and concentrates for 1 minute receives a Fragment of Possibility, which looks like a Tiny, grayish bead of energy that follows the creature around, staying within 1 foot of it at all times. The fragment lasts for 8 hours or until used. Once the beacon grants a Fragment of Possibility, it can't grant another until the next dawn. A creature with a Fragment of Possibility from a Luxon beacon can't gain another Fragment of Possibility from any source.

When a creature with a Fragment of Possibility makes an attack roll, an ability check, or a saving throw, it can expend its fragment to roll an additional d20 and choose which of the d20s to use. Alternatively, when an attack roll is made against the creature, it can expend its fragment to roll a d20 and choose which of the d20s to use, the one it rolled or the one the attacker rolled.

If the original d20 roll has advantage or disadvantage, the creature rolls its d20 after advantage or disadvantage has been applied to the original roll.

Soul Snare. If a follower of the Luxon who has undergone a ritual of consecution dies within 100 miles of a Luxon beacon, their soul is ensnared by it. This soul will be reincarnated within the body of a random humanoid baby developing within 100 miles of the beacon.