All this week we’ve been following StartupBus, a hackathon on wheels, where a bunch of strangers come together to launch companies in one week, all while on a bus. If you haven’t heard Monday’s episode, start there.

It’s Friday, the fifth and final day of StartupBus. By the end of today, one company will be crowned the winner of the competition. But before the final pitches take place, a mysterious opponent emerges to challenge the five finalists.