Moon path

Moon path was a spell that created a bridge or stair fashioned from pure moonlight and gave certain protections to those who crossed it.

Users
Originally, specialty priests of Selûne, namely silverstars and guides of Lucha, had a special ability to cast moon path, and priests who commanded the Sun and Travelers spheres could cast it normally. After the Year of Wild Magic, 1372 DR, clerics and others who commanded the Moon domain could cast a divine version of moon path, while the hathrans of the Witches of Rashemen knew an arcane version. A variant was available only to clerics, druids, and rangers initiated into the greatest secrets of the Selûnite church.

Powers
This spell fashioned pure, pale moonlight into a bridge or stair. It was shaped like a ribbon, lacked rails, was white in hue but translucent, and glowed, making it resemble a strip of glass. The moon path could be up to 135 feet (41 meters) long, or more for more experienced casters, and could be shorter as required. Its width could vary from 3 feet (1 meter) to 20 feet (6 meters), as the caster preferred, and it could have different widths over its length.

The moon path linked two locations known and seen by the caster and was fixed to them without need of supports, even in empty air high above known spots on the ground. It could run horizontally as a flat bridge or ascend or descend as a stair, but at an angle of no more than 45°. It had to be straight, continuous, and unbroken; if anyone or anything was in its way on casting, then the spell failed. The moon path itself could not be broken or moved by any known force and was completely stable.

It was generally similar to a wall of force, as it was formed of force and didn't require supports and couldn't be damaged. Spells and magical breaths and gazes could not penetrate it and neither material nor ethereal things could pass through it. However, teleportations like dimension door and teleport could bypass it.

Those walking on a moon path while it stood were protected in other ways while it lasted. Originally, they could not be drained of their life force or hurt by mundane projectiles and they were immune to charm enchantment spells (but still sensed its affects). Finally, avoiding any safety issues about the lack of rails, they simply could not fall off the moon path, whatever the force used. In the later version, up to nine people or more were selected to receive the benefits of a sanctuary spell, which instead warded them against being directly attacked, provided none of them directly attacked anyone. They were also granted the ability to cling to the moon path as if with spider climb. They immediately lost both if they left the moon path for any reason.

Originally, the moon path lasted until it had been completely traversed by at least nine people or at least ninety minutes, more for more experienced casters, whichever came first. Later, it only lasted for nine minutes or more, but had no limit on how many crossed it in that time. In either case, it could be ended early when the caster dismissed it. It vanished when affected by dispel magic  and was destroyed by Mordenkainen's disjunction, a rod of cancellation, or a sphere of annihilation, while disintegrate blasted a 10-foot-wide (3 meters) hole in it. A magical barrier created by a higher-level spell could prevent a moon path from forming or cut through an existing one. Damage to or cutting of any part of a moon path didn't affect the structural integrity of the whole. If the moon path disappeared or was destroyed, those on it fell normally from the height they were at.

Components
Moon path required verbal and somatic components,  The original spell also required a material component in the form of a handful of powdered moonstone. Later, the divine version required a divine focus, while only the arcane version required a material component, now simply a white handkerchief.