Spanish fly

Also known as the blister beetle due to the amount of cantharadin poison carried in their bodies which can cause a very nasty blistering if it comes into contact with your skin. This is an extract from the biodiversity library on poisonous nature:
This beetle is found primarily in warm climates. The poisonous liquid produced by the "Spanish fly" causes festering blisters on skin contact, and contact with the eyes can even cause blindness. A deadly dose is only 30 milligrams. One gram is enough to cause symptoms in 5,000 people. Symptoms are a painful erection in men, bloody diarrhea and intestinal problems. There have even been cases of damage to the heart, kidneys or nervous system.