'Sneak attack' using AOE spells

Question

In Pathfinder a level 10 Arcane trickster gains a Surprise spells feature:

Surprise spells

At 10th level, an arcane trickster can add her sneak attack damage to any spell that deals damage, if the targets are flat-footed. This additional damage only applies to spells that deal hit point damage, and the additional damage is of the same type as the spell. If the spell allows a saving throw to negate or halve the damage, it also negates or halves the sneak attack damage.

So you can use a fireball to deal sneak attack damage every flat-footed foe in spell's AOE. And since it is not technically a sneak attack that means that 30 feet range limit does not apply.

My question is thus: is there any equivalent feature in 3.5? Arcane trickster sadly lacks this feature.

Answer 1

Nothing directly accomplishes this to my knowledge

There is no direct example of a feature like surprise spells in D&D 3.5e to my knowledge. The few things that get closest, so far as I know, are:

Spellwarp sniper: sneak attack with previously-area spells

Not the answer you’re looking for, I know, but for the sake of putting the only answer I’m aware of that kind of accomplishes this, the spellwarp sniper prestige class from Complete Scoundrel uses its iconic class feature, spellwarp, to convert area spells into rays. Rays are eligible for sneak attack and similar, and the spellwarp sniper even has a similar damage bonus feature in sudden raystrike.

Beguiler: cloaked casting is thematically similar

The beguiler from Player’s Handbook II gets a “cloaked casting” feature that increases the saving throw DC and checks to overcome spell resistance for spells cast on someone denied their Dex to AC. This alludes to sneak attack, since it shares that trigger condition, but is mechanically distinct, both in what it does (no bonus damage) and in how it interacts with other material (which is to say, it doesn’t; none of the various sneak attack feats, spells, items, and so on do anything for cloaked casting, and there aren’t any such things for cloaked casting).

Splash weapons: sneak attack with the splash?

Some people argue that when you sneak attack with splash weapons (alchemist’s fire and the like), you can also deal add your sneak attack damage bonus to the splash damage, for splashed enemies that are denied their Dexterity bonus to AC. The rules are annoyingly vague about it, but ultimately the long and short of it is that the rules don’t support that.¹ Splash weapons can sneak attack their primary target; the splashed targets aren’t subject to sneak attack.

Splash weapons are frustratingly awful and a houserule allowing this (possibly in some reduced form, maybe just +1 damage per +1d6 your sneak attack ordinarily adds) would probably be good for the game, but the official rules don’t do anything like that.

1. _{Because the rules are annoyingly vague about it, the full analysis seems out of scope here. This thread does a decent job of it, particularly this post. The “throw a splash weapon” rules under actions in combat make it very clear that your attack damage—that sneak attack could apply a bonus to—is only the hit on the original target, and that the splash is a separate effect after that.}