Chain Spell( Tome and Blood: A Guidebook to Wizards and Sorcerers, p. 39)
You can cast spells that arc to other targets in addition to the primary target.
Any other metamagic feat,
You can chain any spell that specifies a single target and has a range greater than touch. The chained spell affects that target (the primary target) normally, then arcs to a number of secondary targets equal to your caster level. Each arc affects one secondary target. You choose the secondary targets as you like, but they must all be within 30 feet of the primary target, and no target can be affected more than once. You can affect fewer secondary targets than the maximum. If the chained spell deals damage, the secondary targets each take half as many dice of damage as the primary target (rounded down) and can attempt Reflex saving throws for half of the secondary damage. For spells that do not deal points of damage, the save DCs against arcing effects are reduced by 4. For example, a 10th-level wizard casts a chained cause fear on a nearby goblin and can specify up to ten secondary targets. The goblin, as primary target, must make a Will save against DC 14, while those affected by the secondary arcs save against DC 10. A chained spell uses up a spell slot three levels higher than the spell's actual level