Will-O'-The-Wisp (3.5e Monster)

''Feeling trapped in the darkness of the swamps, your despair turns to optimism as you see a glimmer of light in the distance. Following it, you only seem to press further into the bog, but you hope against hope that it will lead you out of your current predicament. But once you finally get close to it, and find yourself in a mire surrounded by corpses of men no doubt victims of a similar predicament to your own, you realize too late that you have gravely erred.''

Will-o’-the-wisps are the souls of those lost in the wilderness. Feeling abandoned and lost to anguish, their souls survived the limits of their corporeal forms and now seek to lure others into a similar fate.

Combat
Typically encountered into choked, desolate marshlands, they take advantage of difficult terrain to gain an edge on opponents. Posing as guiding lights, they prey on the lost and desperate souls that travel alone through their territories or attempt to separate groups by working in concert. Once they have a foe significantly away from possible assistance, they bombard them with beams of light as much as possible.

All of a will-o'-the-wisp's abilities are treated as having an effective caster level of 3rd.

 (Su): When a will-o’-the-wisp is successfully struck for damage, it may take an immediate action to target its attacker (and only the attacker) with a color spray effect.

In addition, someone who passes through the same space as a will-o'-the-wisp (or has their space passed through by the creature) must make a Will save (DC 14) or be affected by crushing despair. A creature cannot be affected by this ability more than once per encounter.

 (Sp): A will-o’-the-wisp’s only legitimate attack is the ability to fire beams of light from their luminescent bodies. This ability is useable at will as a standard action ranged touch attack, functioning in every way as the Sasha's searing light spell.

 (Ex): In natural sunlight or any spell effect that simulates such, a will-o’-the-wisp is rendered invisible. In darkened conditions, however, it is illuminated as though faerie fire has been cast upon it. The will-o'-the-wisp cannot suppress either the invisibility or the light it gives off.