Hourglass of Lost Chances
Wondrous item, legendary (requires attunement)

This magical hourglass, crafted from a material more resilient than steel yet as transparent as glass, contains sand that remains curiously still and does not flow.

While you have the Hourglass on your person, you can utter its command word as an action to activate it. Upon activation, the sand begins to flow from one bulb to the other, a process that continues unabated even if you turn the Hourglass upside down.

While you have the active Hourglass on your person, you can utter its command word again as an action. Doing so reverts the timeline to the moment you activated it. Every event, including death, is undone, but all creatures across the multiverse retain their memories of what transpired during that timeframe. However, any creature that was not within a 1-mile radius of you at any moment while the Hourglass was active experiences this as a sense of déjà vu.

The Hourglass becomes inactive 10 minutes after activation or immediately after you use it to revert the timeline. Once deactivated, it cannot be activated again for the next 7 days.

(Edit for clarity)