Stingray
Everyone of course knows the infamous Steve Irwin story regarding his confrontation with one of these creatures. The most distinguishing and deadliest feature of a stingray is its stinger located on its tail. While attacks on humans are extremely rare, if provoked or accidentally stepped on, contact with the stinger leads to intense pain and muscle cramps. The attack is only fatal if the barb, which breaks off, lodges itself into a vital organ.