Things that don't go bump in the night

AP here-
It is a dark and rainy night and Tonka and I have been walking for an hour and we are almost home....
All of sudden Tonka takes off at warp speed with his tail between his legs and runs all the way to the end of the bungie leash. He stops and stands obviously scared with his head moving back and forth.
Now Tonka has a habit of running forward when people walk past us, which is silly since they pass us and he is now running the wrong way - not sure what he is thinking with that. This is the same type of rush forward but it has ended in fear not joy. We are 20 yards from the house and there are houses on every side and it is about 8:30pm and rainy. There is no traffic, no other dogs out, nothing that I can see or hear but Tonka is acting like something creepy or dangerous is around. In the past 2 years with the blind boy I have learned that if Tonka thinks something or someone is there - it is. We hurried the last 20 yards to the house.