Is there some legit way of giving an Ooze an intelligence score in 3.5e? I mean, without resorting to GM handwaves, or creating custom statblocks.
Yes, there is a rather quick way to do it in fact. Apply the Sentry Ooze inherited template from Dungeonscape p.114 to the creature.
You will lose the ooze's "mindlessness", which mean it can be affected by Enchantment, but it now have feats, skills, and animal Intelligence (Int < 3) in exchange without too much hassle.
Else you can apply any number of templates that require "living, corporeal creature" that improve Intelligence, for example:
- Half-dragon (don't think too much about the logistics) (SRD)
- Paragon (finally, something that is not Half-something else!!!)
- Favored Spawn of Kyuss (Age of Worms Adventure Path)
Or templates that make its Intelligence at least something, like:
- Celestial / Fiendish / Anarchic / Axiomatic (SRD)
Or have an "evil wizard or sorcerer" and apply "Worm that Walk" template (type become Ooze, but still keep mental score (Int, Wis, and Cha)
Dragon vol. 304 has an awaken ooze spell on page 38. It’s on the sor/wiz list at 8th level, and works pretty much the way you would expect it to per the awaken spell. Costs 500 XP.
Annoyingly, though, just as awaken turns the animal into a magical beast (augmented animal), awaken ooze changes the ooze into an aberration (augmented ooze). So you don’t actually wind up with an intelligent creature of the Ooze type, you wind up with an intelligent creature of the Aberration type that has all the properties and traits of the starting ooze (excepting immunity to mind-affecting effects, which the spell strips away when it gives the creature a mind to affect).
If you add the Fiendish template, it automatically raises the Intelligence score to 3
Creating A Fiendish Creature (From the SRD)
"Fiendish" is an inherited template that can be added to any corporeal aberration, animal, dragon, fey, giant, humanoid, magical beast, monstrous humanoid, ooze, plant, or vermin of nongood alignment (referred to hereafter as the base creature).
Abilities: Same as the base creature, but Intelligence is at least 3.
Also, you can use these templated oozes from the Elite Opponents articles: http://archive.wizards.com/default.asp?x=dnd/eo/20040521a.
Here's a few alternate gelatinous cubes for good measure:
Advanced Bestiary has the Id Ooze template which makes oozes intelligent and the Ooze Creature template which can turn intelligent creatures into Ooze.
Now just imagine putting the Ooze Creature template onto an Awakened Ooze, it'll be back to where it was but with the INT intact. Note that Advanced Bestiary is a 3rd party publication.
Advanced Bestiary also has the Savant template which has Ooze as one of it's options in it's table. It grants +10 INT