Visit Subconscious

You and up to eight other creatures who link hands are transported into one specified creature’s mind. You decide which creature. All linked creatures project an idea of themselves into a demiplane resembling the physical manifestation of the creature’s subconscious. The creatures may appear as the selected one perceives them, or simply as they do physically. The DM can decide where you arrive in the demiplane.

While in the demiplane, your physical bodies remain in the plane of existence from where you cast this spell. Physical bodies are unconscious. Time passes much slower in the demiplane than in your own, so sustenance and aging may not be relevant. One year in the demiplane equates to an hour in your original plane (or the timescale can be at the DM’s discretion).

Damage dealt in this demiplane does not transfer back to your physical body. However, if you or any linked creature drop to 0 hit points, that creature must make a DC 16 Intelligence saving throw. On a failure, the spell is ended for them: they return to their physical bodies, they take 6d6 psychic damage, and are insane until they finish a Long Rest. While insane, they can't take Actions, can't understand what other creatures say, can't read, and speak only in gibberish. A Greater Restoration spell cast on the affected creature ends this effect.

If a linked creature (but not you - the caster), drops to 0 hit points, only that creature is returned to their bodies from the spell/demiplane. Only if you - the caster - drop to 0 hit points will all creatures be returned to their bodies.

Attempting to exit this demiplane (by entering a different plane or through other methods) will end the spell.

You may choose to end the spell, at any time, by using your Action. This ends the spell for all linked creatures.