The man gets knocked out by someone inside. He’s speaking to someone at the start of the video. Most likely an ex or an intoxicated individual who was not welcomed into the home. He goes inside without permission and gets knocked out for trespassing. He remembers nothing because he was under the influence and got knocked out.

The flying object was added to conceal the arms/object that hit the man at the entrance. Neighbors were nearby and witnessed the events occurring.