Luna's response didn't ease her mind when she gave a forlorn sigh before explaining. "The Tantabus was designed to create a nightmare from the dreamer's deepest, darkest fears. Mine is to relapse and become Nightmare Moon once more. Every night under the Tantabus' control, I would do just that. From that point forward, it would become the Nightmare's worst fear, failure. The Elements would show up and defeat her. Neil's worst fear on the other hoof, is us."