Fire Ants!

The odds that you will die as the result of a Fire Ant Bite are
1 in 5,000,000 (0.00002%)

Yeah, so my dad made me watch this movie when I was five or so and it scarred me for life. If only I had understood at the time the odds against a radioactive spill transforming a colony of ants into giant bloodthirsty destroyers of mankind. Instead of running the math, I just didn't sleep for a year. Thanks Dad!

(http://www.safe2use.com/pests/fireants/fireants4.htm)