The dread witch prestige class offers the ability fearful empowerment:
Fearful Empowerment (Su): Starting at 3rd level, once per day you can add the fear descriptor to any spell you cast that has some sort of visual manifestation. For example, you could apply it to a fireball, to a summon monster spell, or to any visual illusion, but not to charm person, since that spell does not directly create any visual effect. Creatures targeted by a spell modified by fearful empowerment must make a Will save (DC equal to 10 + your class level + your Cha modifier) or become shaken for 1d4 rounds; this is in addition to any other effects the spell might have. Your save DC bonuses from master of terror apply to this spell.
(Heroes of Horror, pg. 98-99)
Explicitly noted here is that fearful empowerment works with a summon monster spell, but then the effect of fearful empowerment is to attempt to render shaken anyone “targeted by a spell modified by fearful empowerment.”
Summon monster doesn’t target any creatures; it summons a monster. How does a fearfully-empowered summon monster work? Is everyone attacked by the creature, or otherwise targeted by its abilities, subject to the effect? Or is it merely that being in the presence of such a summoning that’s frightful—and if so, how close must one be? Do you have to be able to see it?
I suspect the strict RAW answer here is simply “you can cast a fearfully-empowered summon monster spell, since summon monster is explicitly a legal subject of the fearful empowerment ability, but since summon monster never targets anyone, no one is actually subject to the fearful empowerment effect and you just wasted your daily usage of the ability.” That being the case, does anyone have any experience running a dread witch actually using a fearfully-empowered summon monster to some actual effect? What are the pros and cons of running things that way—is that how you would still run things? Is there a solid best practice to follow here? Or is “just pick something else” really the best answer here?