Demiplane

You create a shadowy door on the target. The door is large enough for Medium creatures to pass through. The door leads to a demiplane that appears as an empty, 30-foot-cube chamber made of wood or stone. When the spell ends, the door disappears from both sides, trapping any creatures or objects inside the demiplane.

Each time you cast this spell, you can either create a new demiplane, conjure the door to a demiplane you have previously created, or make a door leading to a demiplane whose nature or contents you are familiar with.