WARNING: The following contains spoilers for Batman Superman World's Finest #1, on sale now from DC Comics.

Many would point to the Joker as the one villain in Batman's rogues gallery that Superman should worry about. After all, the Clown Prince of Crime is responsible for his downfall in the Injustice universe. Of all of Batman's villains, he's the one that even the Justice League fears. However, there's one of the Dark Knight's enemies that the Man of Steel should fear even more - one with some of the most terrifying powers in the DC Universe.

That person just appeared in a supervillain team-up in Batman Superman World's Finest #1 (by Mark Waid, Dan Mora, Tamra Bonvillain, and Aditya Bidikar). The Man of Steel's rogue Metallo teamed up with Gotham's very own Poison Ivy. Whilst Batman and Robin dealt with their villain and Superman his, things could have gone even worse if the Last Son of Krypton had faced off against Pamela Isley.

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Superman has faced Ivy before, most notably in the "Hush" storyline (by Jeph Loeb and Jim Lee) in the Batman comics. Poison Ivy used a Kryptonite-laced lipstick that, when applied, allowed her to mind-control the Man of Steel. This was a truly terrifying concept, as the powerful hero nearly killed Batman whilst he tried to undo Ivy's influence. It was perhaps the closest the World's Finest have gotten to a fight without limits. The Dark Knight was able to undo the mind control by having Catwoman throw Lois Lane off a building. Although it worked, there was no way anyone could have known for sure that it would. Batman simply had faith that his friend could break free.

Superman isn't the only Kryptonian Ivy has had wrapped around her finger. During Tim Drake and Conner Kent's first team-up in 1996's WF3: World's Finest 3 (by Chuck Dixon, Karl Kesel, and Tom Grummett), Superboy came face to face with the villain and instantly fell for her mind-controlling pheromones. Most likely the reason he succumbed to Ivy's control without any Kryptonite was because of his half-human DNA. However, the fact that the Kryptonian half of his biology offered no resistance whatsoever is worrying.

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The only sliver of hope comes from Supergirl. In Superman/Batman #19 (by Jeph Loeb and Ian Churchill), Ivy tried the same trick she did in "Hush." She applied her Kryptonite lipstick and kissed Supergirl, hoping to turn her into her obedient servant as she did to her cousin. However, for some reason, it did not work. It may be that synthetic Kryptonite doesn't work on the Girl of Steel or perhaps it had something to do with age or how long each had been exposed to Earth's yellow sun. Whatever the reason, it indicates that Ivy may not be able to control Kryptonians on every occasion she tries.

That's not to say that mind control is the only trick up her sleeve. She can control any plant, which would include the Black Mercy from the famed story "For the Man Who Has Everything" by Alan Moore and Dave Gibbons. It was only the intervention of Batman, Robin and Wonder Woman that freed the Man of Steel from that plant's deadly dreams. There are sure to be plenty of other plants that could injure or even kill Superman, and Ivy would naturally be able to control any one of them.

That's why she's the Batman villain Superman should avoid at all costs. The last time he encountered her, it all almost ended in disaster. The Joker may have the cunning to manipulate the Man of Steel but Ivy has the powers to not only destroy him but turn him into her deadly weapon, which is arguably worse than anything the Joker could ever do.

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