China has a major wasp problem right now. Over the past three months, 21 people have died as a result of wasp stings in the province of Shaanxi alone.
The killer variety responsible is thought to be Vespa mandarinia, or, "Asian giant hornets." They are typically 2.2 inches long, and attack in swarms. Don't think you can run away, either. These things will chase you, and can fly at speeds of nearly 25mph.
Just in case you are yet to grasp the sheer horror, here is a photo.