10 Ways To Beat Superman
4. Too Little/Too Much Sun
Superman owes a lot to Earth's yellow sun as its rays are what give him his incredible powers. However, the very thing that makes him Superman can also be his undoing.
Much like one of those rubbish solar powered toys, Superman is pretty useless if you cut off his access to the Sun. When his cells aren't being bathed in solar radiation, he quickly loses his strength and powers and can be taken down as easily as any schmuck in a cape.
It's not just too little sun that's bad for Kal-El though. In the excellent series All Star Superman, Superman saved an experimental science team who had gone to explore the Sun. However, in doing so he overloaded his cells with solar radiation and his body began to break down, leaving him with only a year to live.
An even more brutal version of this happened in the Justice League story Tower of Babel. Ra's Al Ghul used a new form of kryptonite that Batman had made as a contingency plan which turned Superman's skin translucent. Without any way to filter out the sunlight he was absorbing, Clark's cells were thrown into overdrive and he was incapacitated by the constant agony.