Shadowknight1
Warrior
A plant elemental created by The Green and the consciousness and memories of Dr. Alec Holland, the Swamp Thing is a powerful and intelligent creature born in the swamps of Louisiana when Alec Holland, set aflame and drenched in his own bio-restorative formula, fell into the swamp waters. Swamp Thing initially believed himself to be Holland, but that was not the case. Swamp Thing is THE plant elemental for the Earth and is in contact with all plant-life on Earth. He also has superhuman strength tied to his connection to the Earth and essentially lives on energy from the Sun(sounds like another superhero we all know). Swamp Thing has control over all plant life and can use it to ensnare or traps enemies and has even threatened to cause microscopic flora in his enemies to grow and kill them from the inside. Swamp Thing has no qualms against killing if need-be. Swamp Thing is immortal and can transfer his consciousness to a new body if the one he's inhabiting is destroyed. To give an example of how badass Swamp Thing is, when his wife Abby was held by Gotham City's courts, being charged with crimes against nature(because of her relationship with Swamp Thing), he showed up and demanded her release. When they wouldn't, Swamp Thing overgrew the City and told them that it would remain that way until she was released. The Batman showed up to convince him to withdraw, and when he wouldn't, they fought. Swamp Thing seriously outmatched the Batman, who then convinced Gotham's mayor that it would be in everyone's best interest to release Abby.
So. Immortal, super-strong, complete control over plants, and has beaten the crap out of the "I can beat anyone" Batman. What's not to like?