For example, the Wonder Twins.
These two heroes have not gotten a break ever since their tenure among the Super Friends, alongside the likes of Invisible-Plane Wonder Woman, Giant-Seahorse-riding Aquaman, Black-Lightning-ripoff Black Vulcan, and those other three whose names unfortunately elude most mainstream superhero fans (Apache Chief, Samurai and Eldorado, for anybody besides me, who also cares). That said, these two, if taken into any serious capacity (and hopefully barring the further use of their ridiculous catchphrase 'Wonder Twin powers, activate!'), are not to be messed with.
A pair of fraternal twin siblings from the alien planet Exxor, Zan and Jayna possess the power to shapeshift any time they make physical contact. Zan could assume any form composed of any phase of water (whether solid, liquid or gas, and in any number of different shapes), while Jayna could assume the form of any animal (including extinct and alien creatures, as long as they weren't sentient--couldn't turn into another humanoid shape).