Best way to reduce a creature to Int 2?

[Amechra]

Alright, I want a pretty much failproof way to give a creature enough Intelligence Drain that it only has an Int of either 1 or 2 (preferably 2).

Why?

Special: You can use this skill on a creature with an Intelligence score of 1 or 2 that is not an animal, but the DC of any such check increases by 5. Such creatures have the same limit on tricks known as animals do.

A druid or ranger gains a +4 circumstance bonus on Handle Animal checks involving her animal companion. In addition, a druid’s or ranger’s animal companion knows one or more bonus tricks, which don’t count against the normal limit on tricks known and don’t require any training time or Handle Animal checks to teach.

If you have the Animal Affinity feat, you get a +2 bonus on Handle Animal checks.

Italicized section. It is trivially easy to hit a DC 32 skill check (the highest pre-epic skill check for Handle Animal), and there are a couple of awesome things you could do with this (I'm thinking a group of pet sorcerers and such.)

Basically, I'm thinking of making a Neutral Evil Slaver (no idea on current build; probably will have levels in Marshal, however, for the ever-delicious Motivate Charisma aura), who reasons that, well, all humanoids descended from animals at some point, there is nothing inherently wrong with treating them like animals.

[Kajhera]

Use a Vacuous Grimoire (6000gp cursed item) to time it one point at a time (for Intelligence, 2 points Wisdom), casting Restoration when their Wisdom gets too low, until they hit 2 Intelligence.

[Rebel7284]

Greater Bestow Curse also does this.

[Amechra]

Hmmm... alright, are there any low level ways?

I mean, I forgot about Bestow Greater Curse (Hell, I could probably just Wand it from the Demonologist spell list, where it is a 4th level spell), but I would prefer a cheaper method.

Also, anyone know any good 3rd party tricks? I know about pretty much every trick from WotC sources (thank you, Realmshelp!), but are there good ones in, say, BoEF (yes, I went there.)?

EDIT: If I'm not allowed to use Greater Bestow Curse (the DM doesn't have the SpC, sadly), I could always spam regular Bestow Curse; it would take more uses, but it really only takes 2-3 applications for a normal human.

Now to get over the pesky fact that the Extra Tricks feat can only be taken by Animals and Magical Beasts... Oh well, if I choose to do this to a bunch of good humanoids, and I get a chance to choose their feats (Psychic Reformation looks like the best bet), Nymph's Kiss and being human will give them 3 skill points per level. Pick the right ones, and...

[Maat Mons]

Hmmm… alright, are there any low level ways?

You could use wyrm wizard (Dragon Magic) to get greater bestow curse as early as 8th level. 

Would the DM let you take handle humanoid if you played an anthropomorphic cat? 

If I'm not allowed to use Greater Bestow Curse (the DM doesn't have the SpC, sadly)…

Does the DM have Book of Vile Darkness, Complete Divine, or Races of Destiny? 

[Amechra]

He probably would allow me to take Handle Humanoid, but I don't want to play a cat. I might play a guy who owns a cat, but not a cat in and of itself.

And he does have BoVD, which I just noticed contains the spell (now that you mentioned it). Lucky, lucky!

And I just remembered the good old "1d4+1 Loved Ones get afflicted by an effect from Bestow Curse." clause.

Damn, I love making entire families idiots simultaneously, don't you?

[Shadowhunter]

If you don't have access to the SpC, I wager you at least have access to the PHB.
Feeblemind.

Of course, it's a 5th level spell so it's not low-level, it's mid-level.
On a failed Will save the targets INT and CHA is set to 1.
Permanently. Or until you hit it with a Wish (limited or normal), Miracle or Heal.

[Lycanthromancer]

Baleful Polymorph and Polymorph Any Object will do it (on failed saves, obviously).

You'll just have to turn them into monkeys so they retain functioning hands.

[Amechra]

I actually was thinking about Feeblemind, but since I can Wand some Bestow Greater Curse lovin', I'm going that way instead.

Also, what are some really obscure sources of tricks for animals? I mean, a bunch of them are good to teach your average humanoid, but I really want something where I can order them to perform a certain skill... might have to homebrew that one  (Mostly because I want to train a humanoid to do stuff like Ride or work out in the fields; also, training a humanoid to use Handle Animal on the other slaves is great for recruitment/training/controlling them).

Fun fact: BoEF+Perform trick=bad images in your head  (Find me some high Charisma humanoids!).

And I did manage to find a feat that allows me to train creatures of a specific creature type who are at Int 4 or below, which means that I could control certain creatures without having to negatively impact their intellect. Also, it is left rather nebulous whether or not they still receive tricks based off of their Int... if so, 12 tricks is nice.

[SolEiji]

I imagine, besides permenant magical effects like curses and feeblemind, you'd want ability drain rather than damage as the body can naturally heal damage.  Perhaps subject them to an undead pet?  None come off the top of my head that deal Int drain though.

[The_Laughing_Man]

@Amechra, Hilarious find, kudos! It gave me a good laugh! 

Edit, you could start making poisons that target int. Or make some minor creations..

[Amechra]

Note to self...

Big T is not immune to Bestow Curse's ability score reduction...

What is the minimum level at which we can hit it with it and then shout "Down boy, down!", and have the Tarrasque obey?

[Noliar]

He's only Int 3. The problem is SR 32 and Will +20.

11 levels of Factotum will let us cunning breach the SR. We could spam with a wand until we're out of inspiration and hope big T rolls a one before he eats us.

OTOH Touch of Idiocy does not allow a save 

[Amechra]

Touch of Idiocy it is then.

Which means we have a 3rd level ownership of the Tarrasque scenario.

[Noliar]

Touch of Idiocy it is then.

Which means we have a 3rd level ownership of the Tarrasque scenario.

Where are you getting the penetration at level 3?

Edited to add: not to mention the tumble checks or DD to deliver a touch spell to big T without dying.

[Jackinthegreen]

Touch of Idiocy it is then.

Which means we have a 3rd level ownership of the Tarrasque scenario.

Where are you getting the penetration at level 3?

Edited to add: not to mention the tumble checks or DD to deliver a touch spell to big T without dying.

Spectral Hand says hi.

[Tshern]

He's only Int 3. The problem is SR 32 and Will +20.

11 levels of Factotum will let us cunning breach the SR. We could spam with a wand until we're out of inspiration and hope big T rolls a one before he eats us.

OTOH Touch of Idiocy does not allow a save 

A Wizard 7 using UMD on some Beads of Karma and casting Assay resistance already has this at 11+10. Add in an Ioun stone, Arcane Mastery any other caster level boosts and you have what you need. There are plenty of options.

[awaken_D_M_golem]

Damp Power in CPsi, can reduce a die range to it's lowest amount.
Say instead of doing d6 Int damage, you'd just do 1.

Maybe Poisons can be affected by this. But they work anyway.
It's obvious when you get to zero, and then heal them by the 1 or 2.
Lesser Restoration or wonky Psi stuff.

Capture something first, then go about reducing the Int bit by bit, with whatever.
(iirc - whatever is c.o. speak for idk)