COPY_OF_Demiplane

Choose a creature in range. That creature must then make a constitution saving throw of 20+, ignoring any modifiers. If they fail, they are transported to a demiplane that appears to be infinite the ground is made of darkly colored stone.  Within the demiplane, knives whip in random directions, dealing 10d10 slashing damage per round. This ignores damage immunities and resistances. When the spell ends, the room disappears, and any creatures or objects inside the demiplane are transported to where they last stood.

Each time you cast this spell, you can create a new demiplane, or have the stone door connect to a demiplane you created with a previous casting of this spell.