Tell him he's cross-eyed.
Spray hair-spray into his eye.
Tell him that 9 fingers really isn't enough for a King of ME.
Offer him to tutor him in music. Particularly in singing.
Ask him if he ever blinks.
Present him with a fake Ruling Ring.
Through sand in his eye.
Tell him that a hairy midget will destroy him.
Knock on Barad-dur's gates and say "pizza's here!"
Tell him that there are atom bombs prepared in Minas Tirith, and his best weapon is a rusty musket.
Tell him that his eye would be more attractive if it was green.
Say "Huan" in his earshot (eye-shot?)
Remind him that he doesn't have a license to use a palantir.
There are so many ways!