Noteworthy Achievements, Events, Feats and Blunders of Every Conceivable Kind

The Malaysian government decided to solve their disease-carrying mosquito problem by spraying the infested areas with DDT. This worked, but the cockroaches then devoured the dead mosquitos. This was followed by the region's gecko lizards consuming the roaches. The geckos did not die from the residual poison (surprisingly), but their central nervous systems were greatly affected, causing the lizards to slow down. Moving up the food chain, the cats ate the slow-moving lizards and started to die off in large quantities. Of course, fewer cats means more rats, and the country's rat population soared. As a result, the World Health Organization was forced to step in and ban the DDT. In an effort to restore the ecological balance, they flew in planeloads of cats to kill the rats.

Source: The Best, Worst and Most Unusual: Noteworthy Achievements, Events, Feats and Blunders of Every Conceivable Kind by Bruce Felton and Mark Fowler.