Intelligent items with low ability scores

I'm creating an intelligent item for a goblin PC -- a Bhargest Orb which will improve his natural goblin abilities. I want to give it low mental ability scores to represent its feral nature. There are rules for increasing ability scores for intelligent items, but none for reducing them. How do I handle this? Do I simply reverse the increased ability score table? Start subtracting cost and ego the further I get from 10? Or do I set the ability score at a low level and leave the price and ego alone? Thoughts?

Naaah. Give it standard or even above standard mental stats, but say that those mental stats express themselves in savage, feral and barbarous ways. Otherwise you're handing out free power to players, and removing the limiting factors.

Feral doesn't have to mean stupid.

A 10 in an ability score is average. Nothing special. If you've ever driven in rush-hour traffic, you know what it's like when you're surrounded by "average" IQ drivers, nothing special, who can be quite feral and savage too...

Just set the stats as low as you like them to be and pay for the normal ones. Low stats are not gonna be a bad thing so it wont be worth a discount.

Just set the stats as low as you like them to be and pay for the normal ones. Low stats are not gonna be a bad thing so it wont be worth a discount.

Indeed, anything that reduces an item's ego score is extremely beneficial for the players. Otherwise, one day when they are fatigued and wounded to within an inch of their life, the item will TAKE CONTROL!!!