If you dream that a human transformed into animal & it attacked you, it may mean that human has used their natural traits. For example, animals have basic primal instincts for survival. It will attack, defend and fight for food, water, territory and its young.
In your waking life, you may be facing someone who is competing with you for resources. That person may be prepared to fight unfairly. You may have received some hints about the behaviors of this rival. This dream is a warning & reminder of this threat.