Small & Deadly
Spiders are quite tiny usually, but there is just something about the creepy-crawlers that send a chill up most of our spines. The venom of a Black Widow, in particular, can cause muscles spasms and even heart failure. A little girl in Massachusetts was bitten by one, and immediately she was struck with a fever. She was lucky, though, because the spider didn't release enough venom to stop her heart.