Moonfire

This spell unleashes a flash of “cold white fire” akin to bright moonlight in appearance that begins at any point within range chosen by the caster and flows out from that spot in a straight line away from the caster for 30 feet in a 10-foot-wide strip. All undead creatures within this area suffer 2 points of damage per level of the caster (no saving throw) to a maximum of 20 points.

Moonfire also chills living creatures, doing 2d4 points of damage to those who come into contact with it. It also has the property of revealing all magical auras (including such things as not-yet-triggered fire traps, glyphs, and symbols) that it touches, outlining them with a brilliant greenish radiance. The area where a moonfire spell has taken effect repels electricity for 1d4+2 rounds thereafter, and can deflect lightning bolts and similar magical effects, harmlessly diverting them elsewhere.