He-Man needed someone who could almost equal his strength, so Skeletor is there to balance him out. Although, in the cartoon, he's always getting into mishaps and making tons of mistakes. If a skeleton supervillain isn't a terrifying thought to begin with, I don't know what is.
Just looking at Venom gives me the creeps. Seriously, that mouth, tongue and teeth is more than enough to score him a place on this list.
This guy looks dirty, and might just stab you in the throat when you're not looking. He really doesn't look like a fair-game kinda guy. Plus he spent his whole time polluting the world. That's gotta be seriously evil.
This guy with his shrieky high voice isn't just weird looking, he's pretty damn violent. Granted, DragonBall itself is violent. This guy won't hesitate to wipe out whatever or whomever is in front of him.
You might only be seeing his hand most of the time, but a man with so much mystery around him is probably a very dangerous one.
A warrior with kung fu skills and an army of weird looking things to help him conquer the world, if the cartoon version of him wasn't that toned down, we're pretty sure one, if not all of the turtles would be dead by the second episode.
Don't let this guy's mummified appearance fool you into thinking he's just ugly and evil looking because this isn't his true and best form. He's such a nightmare, he's got evil oozing out of his pores. Plus when he returns to his usual appearance he looks like:
The stuff of nightmares.
Batman may have a lot of enemies, but The Joker is truly his match. This guy may not have any superpowers per se, but he's so crazy he may actually be the yin to Batman's yang.
If the word Doom didn't warn you about how evil this guy is, then how about just taking a look at his overall getup. Plus he's pretty powerful, so much that it takes at least four of the Fantastic Four to stop him. Which is the whole team.
If Mumm-ra had a cousin, SkullMaster would be it. And he would be Skeletor's more ambitious younger brother. He also had magical and psychic powers which makes him pretty bad and a nightmare to deal with.
Not only is she creepy, she's also super cunning and slick. She can also triple in size and topple a ship. And if that doesn't scare you, her face will.
Gargamel always gets outsmarted by those blue little creatures. While he looks like just a dodgy old man with bad teeth, he also wants to eat them. EAT them!!
If Maleficent was in Sailor Moon, this would be her. Except, probably a little hotter perhaps.
Wanting to skin 101 Dalmatians so she can make a fur coat is not where you should draw the line at. Wanting to skin even ONE is where you have to label this woman deranged, crazy, and just mental.
This guy wanted power, like every other politician, and probably wanted to rule the world if he could. Plus that mustache just looks douchey. He's evil personified!