As she was being attacked by a swarm of two or fewer wasps she used her awesome shrieking powers in combination with a crazy dual arm protective flailing motion while running away.
Susan's never been stung by anything except skeeters. It may have been payback for an earlier incident in which she murdered a family of wasps. Who knows. She ended up smashing this one too.
Beware wasps! You have now made an enemy of Susan.