More Neutral:
* Extraterrestrial: This is a more scientific term, often used in discussions about space exploration.
* Non-human: This emphasizes the difference from humans but avoids negative connotations.
* Otherworldly: This highlights the mysterious and unfamiliar nature of the being.
* Visitor from another world: This emphasizes their origin.
More Positive:
* Cosmic traveler: This suggests adventure and exploration.
* Celestial being: This conveys a sense of wonder and awe.
* Interplanetary voyager: This implies intelligence and purpose.
* Spacefarer: This is a more modern and less formal term.
More Negative:
* Outsider: This implies a sense of difference and possibly hostility.
* Stranger: This is similar to outsider but less specific.
* Unfamiliar being: This emphasizes the unknown and potential danger.
Ultimately, the best word depends on the specific situation and the overall message you want to convey.