"It's a Survivor first. What goes down has never happened before," Probst tells PEOPLE. Furthermore, "It is an absolute game-changer because the alliances that were firmly in place are no longer in place and it really sets the stage for a great finish because it truly is anybody's game at this point."
In 20 seasons, Probst has seen his share of milestones, from medical evacuations (Mike Skupin) to blossoming romances (Rob and Amber), but the events on day 30 this season have him shaking his head.
"Survivor fans will be completely shocked," Probst says. "Then after a moment of reflection, not shocked at all, and then after another moment, really annoyed! Finally, when it's all done and they're getting ready to go to bed, they will say, 'Wow, this totally changed the game, and now, I really can't wait to see what happens and who makes it to the finale.' "
The host adds, "It will touch all kinds of emotions. If you are a Survivor fan this season, tonight's episode will absolutely on one hand thrill you and on the other hand, it will frustrate you. But either way you will be excited for how this game is going to finish."
Tell us: What are your predictions for tonight's Survivor?