The Riddling Glass

Wonderous Item, legendary (requires attunement)

The wielder of the glass poses a riddle to a target. It can attempt to answer the riddle or make a DC 25 Intelligence Check to deduce the answer. The timer runs for 5 rounds of combat/30 seconds. If the riddle is not solved by the target(s) in that time, the wielder may use one of the Sphinx Lair actions on initiative count 20 of the 5th round. Each lair action may only be used once per long rest.

Sphinx Lair Actions:

1) The flow of time is altered such that every creature visible within 60' radius must reroll initiative. The wielder can choose not to reroll.

2) The effects of time are altered such that every creature in the lair must succeed on a DC 15 Constitution saving throw or become 1d20 years older or younger (the sphinx's choice), but never any younger than 1 year old. A greater restoration spell can restore a creature's age to normal.

3) The flow of time within the lair is altered such that everything within moves up to 10 years forward or backward (wielder's choice). Only the wielder is immediately aware of the time change. A wish spell can return the caster and up to seven other creatures designated by the caster to their normal time.

4) The wielder shifts the target and up to seven other creatures it can see within 60ft. to another plane of existence.

Credit: Jeff Andrews (pinterest.com/pin/337136722080827846/)