This driver made an abrupt and unsafe lane change directly into my path without ensuring the lane was clear on the freeway of 880, nearly causing a collision. I had to react immediately to avoid hitting his vehicle and honked to alert him to the danger. Instead of slowing down or acknowledging his actions, he accelerated away. We later took the same exit, and I eventually caught up with him. When my vehicle was ahead of his, I observed him laughing and mocking me rather than showing any concern about the near-collision he had caused. His behavior was extremely concerning and demonstrated a disregard for the safety of other motorists. An unsafe lane change like this could easily result in a serious accident. I have photographic evidence of both the vehicle’s license plate and the driver’s face. He stopped laughing and mocking as soon as he saw I was taking a photo and drove away. I am reporting this incident to document the driver’s dangerous behavior and warn other motorists to exercise caution around this vehicle.