1. A super 'tard.
2. Someone who messes up so bad they cannot even ride the short bus.
Jimmy(not real name), decided he had his truck paid off and did not need any insurance save liability. On the way home from the BBQ decided to take the grill home for his buddies. However the coals were still hot and the wind on the freeway knocked over the grill and excited the burning coals. Setting his truck on fire. Jimmy must have looked like a real astrotard standing beside the road watching his truck burn. True story.