You can use this skill [Intimidate] to cause an opponent to become shaken ( -2 penalty to attack and saving throw rolls) for a number of rounds. This shaken condition doesn’t stack with other shaken conditions to make an affected creature frightened. The DC of this check is equal to 10 + the target’s Hit Dice + the target’s Wisdom modifier.
In short, you could use Intimidate on another creature to lower its attack bonus. Basically the counterpart of Taunt. I wasn't sure if -6 AB would be too much so I just included the quote from Pathfinder where the target becomes Shaken. Either way I'll leave it at that so that it's simple enough to implement.
