You can cast spells that arc to hit other targets in addition to the primary target.
Prerequisite: Widen Spell
BENEFIT
You can chain any spell that affects a single target, has a range greater than touch, and that deals either earth, fire, holy, ice, lightning, shadow, water, or wind damage. After the primary target is struck, the spell can arc to a number of secondary targets equal to your caster level (maximum twenty). The secondary arcs each strike one target and deal half as much damage as the primary one did (round down), and can attempt Reflex saving throws for half of the secondary damage. You can choose secondary targets as you like, but they must all be within 30 feet of the primary target, and no target can be struck more than once. You can choose to affect fewer secondary targets than the maximum (to avoid allies in the area, for example.)
For spells that deal damage and inflict a status effect, the save DCs against arcing effects are reduced by 2.
MP Increase: +3 (a chained spell costs 3 additional MP more than the actual MP cost of the spell.)