Jeff Probst announced that it was a unique powerful Hidden Immunity Idol but never said what it could really do. There is only one of them and Tony has it giving him powerful control. For them to Vote Tony Out, they have to Vote for him in two (2) consecutive Tribal Councils forcing him to play the Super-Duper Hidden Immunity Idol in the first one and then taking him out in the second one.
Look for Tony to take out Woo as those on the Jury are probably more likely to make Woo the Winner. His Best Combo would be taking Trish and Jefra to the Final - both are fairly Useless and are Disliked by most everybody. Jefra is almost certain to go to the Final as she is a Complete Pawn and Critical-Thinking-Challenged.