"You have to play it when you vote," Probst says about how the nullifier is used. "The situation would be, someone is at camp with an idol nullifier. They think you have an idol, or they know you have an idol, and they think you're going to play it tonight. They're trying to get you to play it. They have the nullifier. When they go up to vote, they have a decision to make. If they decide to play it, in private, where no one can see them, they'll say: 'I'm playing this idol nullifier against Josh playing his idol.' They write your name down, and drop it in the urn. It comes time to read the votes, and you stand up and play your idol. You dance around, super proud, and you bring it over to me. I'll say: 'This is a hidden immunity idol …' And then I'll reach into the urn: 'And this is an idol nullifier. Any votes cast against Josh will count.'"
Probst adds that whoever plays the idol nullifier has to play it against whoever will wind up with immunity, in order to accomplish the move. For example, it's not enough to play the nullifier against whoever wields a hidden immunity idol; it must be played against whoever winds up with that immunity, whether it's the original person in possession of the idol, or someone else on the tribe who winds up with that protection. "It's a guessing game," says Probst.
"The first time we play it, it will be a big twist," he continues, "and it'll be anonymous. Nobody will know who played it, except for the player who had it and whoever they told. If you don't stand up and you don't play your idol, then I never show the idol nullifier, and the person who played it blew it."