Scorpions are insectlike creatures (arthropods) that release venom when they sting with the end of their narrow tail. Most scorpion stings are not serious, but the venom of a few species can cause severe, sometimes life-threatening, symptoms.
Scorpions are about 3 in. (7.6 cm) in length, have 4 pairs of legs, a pair of pincers like what a crab has, and a long abdomen (generally called the tail). The bulb-shaped structure at the end of the tail contains the venom and stinger.
One species of scorpion in Arizona and southeastern California of the United States, and other species found in North Africa, the Middle East, South America, India, and Mexico have venom strong enough to be dangerous to adults. A bite from one of these scorpions can cause pain and swelling where a person was stung, numbness, frothing at the mouth, trouble breathing, muscle spasms, and convulsions.
WebMD Medical Reference from Healthwise