Felon said:
Scorching ray seems to be a winner.
You know, I was half-expecting someone to mention a spell from the new Player's Guide to Faerun. Don't tell me there aren't any smackdown spells in there
Hehe, the spells in general are tame and just rehashes of 'Old Spells'. Nothing particularly memorable in it, unforunately. Well except that it's save or die spells are still Save or Die and not Save or Massive Damage...
I'd suggest Prismatic Eye for 'cheesy spell of the week' from PGF though. 6th level spell, summons an that you can control that fires out prismatic sprays (it randomly determines which of the 7 colors to use, and once used up, it's well used up). Save DC of 19 when applicable at least. Still... It's a bit cheesy, especially given that prismatic spray is 7th level

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But again, honestly, I think scorching ray is the best bet for this spell

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Closest subsequent spell I can think of would be Firebrand. It creates class level number of 5 ft bursts that deal CasterLevel d6 (max 15d6) each. Stacking them doesn't increase damage however. [For a nice, Ref half/SR applic feat]. Further you can empower it (to fit the 7th level minimum), giving you an average damage of [15d6 + 15d6/2] ~= 78.75 per burst.
If it's a particularly large creature (well, like say, 10 ft square, you can hit him with 4 bursts - etc). You can deal -alot- of damage. And if you really need to be evil, take Elemental Substitution it to work as you need.
Ok, I've found my new evil spell of the day... "Oh hello mister dragon. Why don't I just learn you elemental vulnerability here and ... oooh lookey, sonic smackdown pain."
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Alas, some sanity may be found in Errata. One creature can only be affected by one such burst... So while it may be evil, it isn't "OBLITERATE THE HUGE CRITTER" evil. Just "OBLITERATE THE MASSES" evil

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