A cat's sudden onset of aggressive behavior can be caused by a variety of factors. Here are some possible causes and corresponding suggestions: Environmental changes: Cats can be very sensitive to changes in their environment. Moving, new furniture, new pets, or changes in family members can all make your cat feel uneasy. It is recommended to keep the environment stable and give the cat enough time to adapt. Physical pain or discomfort: When cats are sick or injured, they may become cranky due to pain or discomfort. If you suspect your cat has a medical problem, take him to the veterinarian as soon as possible.

Insecurity: Cats may become aggressive because they feel neglected or insecure. It is recommended to spend more time with your cat, interact with it, and give it enough care.

Territorial issues: Cats are highly alert to their territory and may become aggressive if other cats or animals invade their territory. Keep your cat's territory safe and avoid unnecessary conflicts.