Source: dc.wikia.com

6. Charybdis

Why doesn’t anybody know who Charybdis is? Not the mythological creature famous for giving Odysseus a hard time, but the DC villain.

The one who took off Aquaman's hand? Yeah, Aquaman lost a hand in the Nineties. It was eaten off by piranhas. Because of Charybdis. Charybdis is a power duper. Meaning he can copy people's superpowers. What makes him especially formidable, however, is that unlike other superpower duplicators, his powers aren't temporary. He keeps the powers he copies.

Yeah, that guy could be the most powerful villain in the DC Universe if he just got his s**t together. During a fight with Aquaman, he fell into a pit of piranhas and became Piranha Man. Sure is an origin. If that's all it takes to give him a new power set, I'd hope he never steps in dog poop.

Why he isn't more popular: His visual design is kind of boring and all over the place. And his personality is a nothing. That's why other media pieces credited other, more interesting, characters for Aquaman's lost hand.