Spirit Gate

Must be cast within a Bone Circle.

This spell opens a gate to the Astral which will last until the next dusk, dawn, noon or midnight. Anything within the Bone Circle at the time it was cast may pass into the Astral, anything in the Astral that finds the Spirit Gate can pass through it.

If the caster wishes to bar passage, then they can do so, in which case anything trying to move through the gate has to beat the force of the spell.