Thank you for sharing this with me. It's important to understand that aggression in dogs can be caused by various factors, such as fear, anxiety, territoriality, frustration, or lack of socialization. Therefore, it's essential to identify the underlying cause of the aggression before working on teaching the dog new tricks.

That being said, providing your Golden Retriever with mental stimulation and teaching them new tricks can be an effective way to redirect their negative behavior and help them develop a positive mindset. Here are some strategies you can try:

1. Start with basic obedience training: Teaching your dog basic commands such as "sit," "stay," and "come" can help establish you as the leader and improve your dog's overall behavior. Positive reinforcement training methods, which involve rewarding your dog for good behavior, are generally more effective than punishment-based methods.

2. Engage in interactive play: Interactive play with your dog, such as playing fetch or tug-of-war, can be a great way to provide mental stimulation and bond with your pet. It can also help redirect their aggressive behavior onto appropriate play activities.

3. Teach new tricks: Teaching your dog new tricks such as shaking paws, rolling over or playing dead can help keep their mind engaged and reduce boredom. This can help prevent them from turning to aggressive behavior as a way to relieve stress.

4. Use puzzle toys: Puzzle toys such as treat dispensers can help challenge your dog's mind and keep them occupied for longer periods. This can help reduce boredom, which can be a trigger for aggression.

Lastly, if the aggression persists or intensifies, it's important to seek professional help from a certified animal behaviorist. They can help identify the root cause of the aggression and develop a personalized strategy to address it effectively.