Just because Power Rangers Wild Force is a more lighthearted series, it doesn't mean it doesn't have dark elements. In fact, Wild Force has one of the darkest backstories for a Red Ranger and let's not get into some of the villains...
- Master Org. Just everything about his presence is terrifying. The idea that this once kind and (formerly) innocent man is capable of such evil, it makes most of the villains from the previous seasons look tame. He's killed Cole's parents as well as some of his minions, attempted to kidnap (and kill) baby Cole, he almost killed Cole's teammates, he's also destroyed the Wild Zords he has caused great destruction to the Animarium... and enjoys every minute of it. There seems to be nothing he won't do in order to gain the upper hand.
- In addition to being creepy, he also looked creepy too. Everything from his soleless eyes to the haunting stares he gives off can give anyone nightmares.
- Even his death scenes are terrifying. When he first "dies" as a human, we actually see it on screen (which rarely happens) only for him to wake up. When he dies as an org, we see his face one last time (as seen above) which shows his haunted death stare before he explodes which leaves behind his blood vessels and Org Heart which is pretty gruesome in it's own right.
- The worst part? He chose to do all of this. He chose to become a monster and brutally murder his friends. He chose to try and destroy the biosphere for spite. Everything Master Org does is because he chose to do it. Which makes him far more terrifying than villains who were made or forced to be evil.
- How Cole's parents died. The newly formed Master Org unleashed vines that Impaled with Extreme Prejudice.
- Mandilok can also qualify, if because he/she has multiple mouths and two minds.