Ysalamiri

As long as Ysalamiri is on the battlefield, {g} mana cannot be used by any player to cast spells. All Jedi or Dark Jedi creatures and planeswalkers become 1/1 Nullified Jedi creature tokens until Ysalamiri is destroyed.
"I presume you're already familiar with the ysalamiri's rather unique characteristics."
--Talon Karrde