How I Would Do It, by Troy Martin
Option 1: I'm a book worm type. If I end up going into a game or taking someone on in an argument I like to be prepared for what is to come. Now being a person with no powers going up against someone who has powers that are close to a god I'm a bit disadvantaged. But there are ways around it, and they are the 2 main weaknesses that Superman is vulnerable to.
So while studying up his weaknesses I would try to find any book of arcane magic. All I need is anything that would create a magical poison that would paralyze the body. I'm sure with the unlimited possibilities with magic that I would find one.
Next step would be to take an ordinary switchblade and coat the blade with the poison, thus making the weapon magical. Now not to make sure that it would be traced back to me, I would go to the local underground bars where most criminals would hang out or members of Intergang and use them to get a hired thug to rob a person in Metropolis and use the switchblade on the Man of Steel who would think it was a regular cheap dime store knife. Thus would paralyze him but also allow the blade to penetrate his skin, where it could be moved around all over a la Bullseye and Elektra if you know what I mean. RRRIIIPPPP!!! Ouch!
Reason for this: Magic and magical objects operate at a chaotic wavelength that Superman can not match nor can he see. Even if he could see the switchblade being hidden, Superman would not think twice of it being a big threat. Though the alloy of the blade is something that normally would not harm Superman in any shape or form, being enchanted by magic makes the alloy run at the chaotic wavelength of the spell. Thus a good stab to the chest or simple cut to the hand to get the spell active, and presto! One very dead Superman! So who needs Doomsday?
Option 2: Kryptonite is the major weakness to Superman and should be to humans, but seeing how there are only 5 pieces of Kryptonite and one of them belongs to Batman, they're kinda rare. One of the Krytonite pieces would probably be in a museum under close study or for display. To me the first part is that I don't need to steal the Kryptonite. I just need to see it for merely 10 minutes, as I'll explain.
Next step is that I create simple transmitter devices that would be placed all over Metropolis mainly on roof tops so as not to harm regular people out and about. These devices would look like simple weather stations. While this act against Superman would not work immediately it would work over time. One day the Man of Steel would fall out of the sky or end up having many years of his life taken away from many days of slow Kryptonite poisoning.
Reason for this: during the 10 minutes I would have been near the Kryptonite I would have used a spectrometer and other devices to find out the frequency and wavelength at which Kryptonite's radiation is emitted. Because radiation affects and degrades us on a cellular level, this would be replicated in a form of low power ultrasonic waves set so that all Superman would experience at first is very very small blurring of his vision, or some minor effects which would go away after he had finished his patrol over the city. With the devices disguised as weather stations and placed on every building it would only affect him, as everyone else below the skyline would be fine. One day we might see in the newspapers something similar to All-star Superman where he knows he is dying, or he collapses out of the sky one day. On the side-effect side Metropolis might see a dramatic decrease in the general bird population. Hmmm...unforseen consequence there.
And that's how I would do it. Though many of you might disagree with me and my methods that's fine. I welcome other ideas and opinions in how you would do it, or if you would ever do it at all. I understand the many problems that would come with the death of Superman. Pretty much all hell would break loose and there would be no silver bullet to protect the planet from cataclysmic dangers. Ah well, we'd just have to deal with it I guess. Of course there's always the rest of the JLA.....