Whirlwave

This spell shapes existing water (no matter how agitated) into a tunnel like that formed by large “breakers” rolling into a shore. This cylinder of water is up to 300 yards long, contains breathable air, and has “solid” walls that will not collapse or spray water on creatures inside, although they can freely reach through the curving water, pierce it with weapons, and even grasp things and pull them through the walls and into the tunnel. A whirlwave tunnel can be traversed as if one is walking on solid ground, and even if cast in a storm, both the water and the air within it are calm and immobile.

The tunnel forms in the direction its caster is facing, beginning around him or at any distance within spell range, and either runs straight away from the caster or, if the caster desires, curves toward a desired destination he visualizes. (That is, the caster must have seen it previously, even if darkness or weather prevents seeing it at the time of casting. The caster cannot merely aim for a harbor or an island he suspects is present.) The caster can choose to “anchor” the tunnel, which makes it immobile despite external forces such as tidal waves, gales, and the like. He could otherwise elect to make it mobile so that it is swept along by the surrounding waters. The latter use of the tunnel usually serves to bring sailors ashore, or most of the way toward shore, from a shipwreck or a naval battle.

A whirlwave tunnel continues only so long as there is water around it. It cannot be longer than the body of water, though it can otherwise be as long as the caster desires, to its length limit of 300 yards. The magic prevents water from flooding the tunnel through its open ends, but fails, causing a tunnel collapse, if struck by part water or similar magic of equal or greater level that serves to shape water. Persistent attacks on a tunnel by a water weird, water elemental, or other creature partially composed of liquid water (as opposed to creatures that merely live in the water, such as sharks or octopuses) can also cause its collapse if they inflict a cumulative total of 66 points of damage in a single 10-foot spot or area. The use of any fire-related magic within the tunnel (even spells cast into the open ends, such as fireballs) also causes its instant collapse, although the two spells will cancel each other rather than visiting fiery damage on creatures in the tunnel (they still suffer damage from the collapse itself)-

A whirlwave tunnel can be created that bends or slopes up or down from the horizontal, and its “floor” is not slippery. Thus, a caster can use this spell to create a climbing chute (but not a slide) within a waterfall and curve safely through a plunge pool at the bottom of the fall or to thrust safely through a whirlpool or maelstrom.

A whirlwave tunnel protects creatures inside it as follows: No normal missile can penetrate its walls. Weapons wielded directly from the outside (for instance, by aquatic creatures), spells cast from the outside, and objects penetrating from outside (such as ships or rocks that come into contact with a mobile whirlwave tunnel) can all pass freely through the walls of the tunnel, with one exception: The swirling waters of the walls prevent clear sight of creatures inside the tunnel by observers more than 10 feet distant, so spells requiring clear vision of the target are affected.

Any number of creatures can pass along a whirl-wave tunnel before it expires, at their normal movement rates. Those still in the tunnel when it collapses, or passing bodily through the tunnel walls, suffer 5d4 points of battering damage (per passage).

The material component is a piece of wire or glue-stiffened thread formed into a hollow spiral (like a metal spring). Also, some of the water is consumed by the spell. (If this spell is cast in a shallow wading pool, the magic works, but it nearly empties the pool in the process.) That this magic does not protect beings in the tunnel from acids, poisons, or other harmful effects in the water itself.