The remaining nine amateur cooks are faced with one of the most intimidating mystery box ingredients to date - "uni," otherwise known as sea urchin. In a surprising twist, the contestants must incorporate the spiky culinary delicacy into their creations, and the amateur cook who presents the most exceptional uni dish will earn a significant advantage in the next round. Later in the elimination challenge, the winner of the mystery box challenge will assign each of the remaining contestants one of eight different types of fish. Find who will impress the judges and whose culinary dreams will sink.