This dream appears to be rich with symbolism and reflects various aspects of your psyche and current life situation. Here are some interpretations and insights:

1. Feeling Vulnerable: The encounter with the group of teenagers and the threat of violence may represent feelings of vulnerability or powerlessness in your waking life. You might be facing a situation where you feel threatened or that your personal space is being invaded.
2. Loss of Control: The act of giving up your possessions can symbolize a fear of losing control or security. It may reflect concerns about your personal identity or resources, such as finances, relationships, or self-worth.
3. Family Dynamics: Being with family during the incident could highlight your feelings about family support or protection. It may suggest you are seeking comfort in your loved ones amidst life's challenges.
4. Aliens as Helpers: The appearance of aliens, who help retrieve your belongings, could indicate a desire for outside intervention or assistance in your life. They might symbolize the unexpected or different perspectives that can aid you in overcoming challenges.
5. Playfulness in Danger: The part where you are chasing each other in a garage suggests a juxtaposition of playfulness and seriousness. It may indicate that even in tough situations, there is room for lightness and connection with others.

Advice: Consider reflecting on areas in your life where you feel threatened or out of control. It might be beneficial to seek support from family or friends when facing challenges. Additionally, think about how you can regain a sense of control and security in your life, whether through practical steps or emotional support.

Overall, this dream points to navigating through feelings of vulnerability while emphasizing the importance of family and community support.