Pressure Sphere

This spell suddenly causes the water around a target to take on the terrible, bone-crushing pressure of the deepest ocean trenches.

(Stormwrack)  
Originally posted on D&D tools

Evocation [Water]

Level: Druid 2, Sorcerer, Wizard 2, Blackwater 2,
Components: V, S,
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Area: 20-ft.-radius spread
Duration: Instantaneous
Saving Throw: Fortitude half
Spell Resistance: Yes

This pressure deals 4d6 points of damage (Fortitude save for half).

The area of the spell can be constrained by the available water; it has no effect on creatures or objects that are within the radius but not in the water, or on squares of water that are not at least 5 feet deep.

The spell must be centered at or below the surface of the water.