Mutiny

Mutiny is a twist in which contestants on both tribes are offered an option to join the rival tribe immediately.

About
A Mutiny can happen in a random point during a game when there are two or more tribes remaining. It will be effective until the tribes merge or a new opportunity to switch tribes shows up (e.g. Tribe Switch).

In some cases, a special stipulation is added to those who take the offer of a Mutiny such as gaining individual immunity in the following Tribal Council.

Survivor: Chile
On Day 17, a Mutiny was offered where only one person from each tribe can take it. Jessy, Seth, Heather, Tyler P. & Cali elected to mutiny.