This dream may represent a situation in your waking life where you are facing a challenge or conflict. The person at the back door of your childhood home may symbolize a problem or issue from your past that has resurfaced. The request for water could represent a need for emotional nourishment or support. By letting the person in, you may be acknowledging and confronting this issue. The appearance of the person in another room could suggest that this problem is not easily avoided and may require your attention. The initial friendliness of the person may reflect your initial approach to the situation, but the sudden lunge and attack could represent your fear or anxiety about facing it. However, your confidence and ability to fight back may indicate that you have the strength and resilience to overcome this challenge. The lack of pain from the bite and absence of fear may suggest that you are not as vulnerable or helpless as you may have thought. This dream may be encouraging you to confront your fears and trust in your abilities to overcome any obstacles in your life.