Dobsonflies are Megalopterans, large insects loved by fishermen because they attract all the best fish in fresh water. They have a bunch of goofy names:
Helgramite, Dam-worm, The Andy, Flying Crabs, Scrabbles, Molly-Grubs, Flying Worms, Stone Crab, Hell Devils, Conniption Bugs, Bogart, Ho Jack, Hiltamites, Snake Doctor, Alugmites, Water Grampus, Hell Divers and many more...
If you see one hanging around a porch light, turn it off. They only have a week to mate.