Enchantment, 2W (3) When Oblivion Ring comes into play, remove another target nonland permanent from the game. When Oblivion Ring leaves play, return the removed card to play under its owner's control.1 A circle of sugar and a word of forbiddance.
Illus. Wayne England
10/1/2007: If Oblivion Ring leaves play before its first ability has resolved, its second ability will trigger and do nothing. Then its first ability will resolve and remove the targeted nonland permanent from the game forever.
10/1/2007: If there are no nonland permanents in play other than an Oblivion Ring, and the card it removed from the game was another Oblivion Ring, playing a third Oblivion Ring will result in an involuntary infinite loop that will end the game in a draw (unless someone chooses to break it by putting another nonland permanent into play or destroying one of the Oblivion Rings, for example).
10/1/2008: If the removed card is an Aura, that card's owner chooses what it will enchant as it comes back into play. An Aura put into play this way doesn't target anything, but the Aura's enchant ability restricts what it can be attached to. If the Aura can't legally be attached to anything, it remains removed from the game forever.