History WesternAnimation / TheUltimateEnemy

* ForWantOfANail:
** [[spoiler: Danny cheating on a test sets off a long string of events that ultimately end with his family, friends, and teacher dead and his ghost half splitting off from him, becoming evil, and attempting to destroy everything. At the end, Danny knows this ahead of time and thus chooses to not cheat in order to avoid this string.]]
** In a different vein, however, [[spoiler:Dark Danny fighting Danny in the climax results in Danny managing to learn the Ghostly Wail ten years earlier than he did originally]].

* ScrewDestiny: At a '''very''' crucial moment in the FinalBattle, Danny manages to [[spoiler:spit in the face of 10 years worth of history and ''use the Ghostly Wail against Dark Danny''. In fact, Danny relentlessly promising to himself, his loved ones, and ''even to his evil future self'' that he will ''never'' become a monster was enough for [[BigDamnHeroes Clockwork to directly intervene]] and allows the boy a second chance to atone his mistakes]].

* TheJuggernaut: Living up to his name, the Ultimate Enemy is almost completely invincible. Even though nobody in the BadFuture can stand him, none of them can stop him as he ravaged the planet. [[spoiler: [=SkulkTech=]'s PowerNullifier is stated to not effect him, and likewise the Specter Deflector doesn't weaken him like it does Danny and Vlad. Even when Danny gains the Ghostly Wail, it's not enough to knock him out. Danny only wins because the enemy being his future self means he can't kill Danny, and even after he's imprisoned in the Fenton Thermos he dents it trying to break out.]]

** Vlad Plasimus is horrified by what [[spoiler:Dark Danny did to his human half, to the point where he outright refuses to elaborate on just what happened when telling the story to [[TimeTravelTenseTrouble Past/Present]] Danny.]]