To dream of a stranger represents an aspect or quality that you refuse to show to others. It may also be suggesting a solution or resolution for an issue that is causing you anxiety.
Hospitality is a trait that softens hard hearts, especially when it is done without expectation and for complete strangers. To dream about hospitality indicates your generous nature.
If you dream about aliens, it symbolizes an unfamiliar or strange situation. This can be viewed in either a positive or negative way, depending on the context of your dream. Feelings of fear when dreaming of aliens indicate that you are either not ready or deliberately holding something back. Feelings of curiosity toward the aliens indicate that you are willing to take a risk and roll with the punches.
The presence of aliens in your dream may also point to subconscious feelings of resentment. Take the time to look at your relationships and be sure to let someone know if they are overstepping boundaries or making you uncomfortable in some way.
Alternatively, an alien in your dream can be symbolic of hope. Dreaming of an alien is your subconscious mind letting your conscious mind know that there is hope in what has otherwise been a seemingly hopeless situation. Do not give up!