Twowolves
Explorer
I once had a wizard character I was playing get Feebleminded by an opposing wizard. Thing was, the bad guy was under Improved Invisibility, and my character was the only one with See Invisible up. The DM ruled that I could indeed "defend myself" with my staff, so everyone else saw my character go slackjawed-drool-on-himself-stupid, then run (well, fly, actually) around the room swinging his staff at apparantly empty air. It had the desired effect, however, as they could target the square my character was attacking (50% miss, but better than 100%) or pelt the area with AoE spells.