Hourglass of Slumber

This ebony and gold hourglass is filled with nebulous clouds of dreamy smoke instead of sand. The hourglass can act as a 1-minute timer, allowing the smoke to filter from one chamber to the next for the duration.

The hourglass has 3 charges and regains 1d3 expended charges daily at dusk. While holding it, you can expend 1 or more of the glass's charges to turn it over and cast the sleep spell from it. For 1 charge, you cast the 3rd-level version of the spell. You can increase the spell slot level by one for each additional charge you expend. This version of the spell has the following changes:

The spell lasts until the hourglass’s timer ends or is stopped, or until the hourglass is flipped again.

Each time a sleeping creature takes damage, it must make a Constitution saving throw, waking up on a success. The DC is equal to 20 minus half the damage dealt (minimum DC 10). After 3 failed saves, a creature automatically wakes up.