When Imperial Mask enters the battlefield, if it's not a token, each of your teammates creates a token that's a copy of Imperial Mask.
You have hexproof. (You can't be the target of spells or abilities your opponents control.)
5/1/2007 This card creates tokens that enter the battlefield as enchantments, not creatures.
5/1/2007 Only teammates within the range of influence of Imperial Mask’s controller will get a token. Imperial Mask’s controller doesn’t get a token; that player just gets the Imperial Mask.
5/1/2007 Each Imperial Mask permanent is independent and affects only its controller and the opponents of its controller.
5/1/2007 If Imperial Mask has left the battlefield by the time the triggered ability resolves, the tokens will still enter the battlefield as copies of Imperial Mask.
5/1/2007 If Imperial Mask becomes a copy of something else after the ability triggers but before it resolves, the tokens will enter the battlefield as copies of whatever the ex-Imperial Mask is now. If Imperial Mask became a copy of something else and then left the battlefield, the tokens will enter the battlefield as copies of whatever it was copying when it last existed on the battlefield.