According to a report from Umberto Gonzales of Heroic Hollywood, Ben Affleck's Batman will use a variation of the Kryptonite spear as seen in "Injustice: Gods Among Us" in order to defeat Henry Cavill's Superman in the upcoming "Batman v Superman: Dawn of Justice." 

In the film's trailer, Batman is shown holding what appears to be a modified rifle while standing in an abandoned building. Rumors across the Internet state that this is Wayne Manor or the same building where Superman killed General Zod in "Man of Steel." According to Gonzales, that long item in Batman's hands is actually a Kryptonite-laced spear. 

A report from Screen Rant also points out that Lex Luthor, played by Jessie Eisenberg, will have to possess Kryptonite as well if he is going to don his super-powered exo-suit as rumored. If Lex is going to fight Superman, then a powered suit won't be enough and the only way he'll have a chance is to have his own collection of Kryptonite. 

Kryptonite wasn't used in "Man of Steel" but the film explained that Superman gets weak when he is close to something from Krypton, not just because of radiation as it is in the comics but because he had spent too many years on Earth that his body now rejects Krypton's natural atmosphere and chemical build. 

It may be possible that Batman has attained some Kryptonian rubble and have re-fashioned these as weapons. According to Cinema Blend, it is also possible that Lex Luthor may have experimented with different forms of radiation to make these Kryptonian rocks into the green Kryptonite that fans are more familiar with. 

There is also a scene in the trailer where Batman appears to be holding a long rifle. According to Heroic Hollywood, this rifle might also be using Kryptonite-laced bullets similar to the one used in Frank Miller's "The Dark Knight Returns" graphic novel of which this film is based on. 

"Batman v Superman: Dawn of Justice" opens in theaters this March 25, 2016.