In my opinion there is no nastier living creature on the planet than the scorpion. It is entirely made from front to back
to hurt you with no redeeming features whatsoever.
Also known as the cuddly "Deathstalker", Wikipedia suggests it is one particularly nasty git:
The deathstalker is regarded as a highly dangerous species because its venom is a powerful cocktail of neurotoxins, with a low LD50 rating. While a sting from this scorpion is extremely painful, it normally would not kill an otherwise healthy adult human. However, young children, the elderly, or infirm (such as those with a heart condition or those who are allergic) would be at much greater risk. Any envenomation runs the risk of anaphylaxis, a potentially life-threatening allergic reaction to the venom. If a sting from Leiurus quinquestriatus does prove fatal, the cause of death is usually pulmonary edema. The German pharmaceutical company Twyford and the French pharmaceutical company Sanofi Pasteur both make an antivenom intended for the treatment of deathstalker envenomations.
One component of the deathstalker's venom, the peptide chlorotoxin, has shown potential for treating human brain tumors [1]. There has also been some evidence to show that other components of the venom may aid in the regulation of insulin, and could be used to treat diabetes.
Neurotoxins in L.quinquestriatus venom include the following:
* Chlorotoxin
* Charybdotoxin
* Scyllatoxin
* Agitoxins type 1, 2 and 3
Take my advice, run...