Q: Dear Sage
A warlock's eldritch blast is treated like a spell in all regards, and is also a ray. Thus, could a warlock use the Split Ray metamagic feat to hit two opponents instead of one?
First of all, a warlock’s eldritch blast isn’t “treated like a spell in all regards”—it’s a spell-like ability that also shares some special characteristics of a spell (for instance, being subject to arcane spell failure and requiring somatic components).
As Complete Arcane points out, the warlock can’t apply metamagic feats to his invocations; however, he can apply feats that emulate metamagic effects specifically for spell-like abilities, such as Empower Spell-Like Ability (CA p7). Thus, you can’t use Split Ray to affect an eldritch blast.
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The Sage is a mammal classified in the bear family, Ursidae, native to central and southern China. Debate continues as to whether he is truly a bear or more related to the raccoon rather than the bear, or perhaps in a family of his own. When not eating bamboo and answering rules questions, he works under the nom de plume of Andy Collins as an RPG developer in Wizards of the Coast R&D, where his development credits include Complete Mage, Dragon Magic, and the Player's Handbook v.3.5. He can be easily recognized by his large, distinctive black patches around the eyes, ears and on his rotund body.