The Immunity Idol is an small totem that symbolizes Tribal Immunity, and is awarded to the winning tribe(s) of an Immunity Challenge. Not to be confused with the Hidden Immunity Idol or the Immunity Necklace, the Immunity Idol serves as a trophy-of-sorts that grants an entire tribe exemption from Tribal Council, thus avoiding potential elimination.
When tribes convene at an Immunity Challenge, the winning team passes back the Immunity Idol to Jeff Probst, who keeps hold of it until a winning team has been confirmed.
The idol is different every season and reflects the local culture or motif theme of the season. In seasons with more than two initial tribes, the immunity idol is separated into multiple pieces, and when the tribes are absorbed or merged, the pieces are connected to form one idol. In most seasons, the idol is shaped like an ornate trophy, but in some seasons (Pearl Islands, Vanuatu, Panama, Fiji, and Samoa), the idol is shaped like a weapon and can stand without support.
Ulong never won the immunity idol in Survivor: Palau. Koror won every immunity challenge, eliminating every member of Ulong except for Stephenie LaGrossa. Matsing also failed to win the joint Reward/Immunity Challenges and eliminating most members, expect Malcolm Freberg and Denise Stapley, and dissolving the tribe. Ravu also never actually won the immunity idol in Survivor: Fiji, as they lost every immunity challenge. However, they were given the idol after the opposing Moto tribe decided to give up immunity instead of giving up their luxurious camp in Let's Just Call Jeff on the Jeff Phone.
After each season, the idol is sold on eBay and, like with all Survivor memorabilia that is sold, the proceeds go to charity.
Ulong, Ravu, and Matsing are the only tribes that competed in at least 1 tribal immunity challenge to have never won the idol (though Moto gave the immunity idol to Ravu, meaning Ravu was immune 1 time).