OMG! Is my neighbors dog possessed or something?

Reminds me of a little poodle mix I saw once. It was barking at a tree shedding white blooms. It would stare at the tree with tail wagging and bark until a blossom fell and he could chase it. Then it would do it it over and over. It was as if the tree was playing with the little dog. Not much to do with your question, but a cute story none the less.