Chrono Lock

School: Chronomancy (Transmutation)
(Intended for use with a Chronomancer subclass such as the School of Temporal Magic)

The caster halts the timeline of a single inanimate object for the duration of the spell. This object can be no larger than 3 feet on a side and weigh no more than 10 pounds. The item does not age and cannot be moved or otherwise interacted with. It behaves as though an indestructible, immovable rod and gains immunity to all damage. When cast, a password can be assigned by the caster to end the spell early. This password must be spoken by a creature touching it. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the duration increases by 1 day for each slot level above 3rd.