I was supposed to be brief.
The assignment was a survey. Drop into orbit around a small blue world, catalogue the dominant species, file a report, leave. Standard work. Naraxians do this constantly. We are a quiet people who like to know things.
I picked a form off the reference shelf. Green, two arms, an agreeable height. Your species had already decided what an alien looks like, so I obliged. It tested well. Nobody looks twice at the alien they were already expecting.