Most people know about kryptonite, and its detrimental effects on Superman. Of course, that's only green kryptonite - there are many other colors and varieties, all with different effects; some good - mostly bad. If you need a refresher course on kryptonite, check this out.
Today we examine red kryptonite.
Red-K (as it is known) was invented sometime early in the "Silver Age" of comics (late '50s/early '60s) as an excuse to introduce more outrageous plots in Superman comics. Red-K causes "unpredictable" results - so the writers could literally use any plot device imaginable - Superman has two heads, turns into a half-man/half-ape... you name it.
Our friends at Topless Robot (???) have compiled the nine "dumbest" effects of red kryptonite. And who am I not to link to it?