There are all sorts of imaginations as to what an alien would be if aliens did in fact exist. There is much debate on the topic with some people believing whole heartedly that aliens do exist, some people believing completely that they don’t, and a lot of people who neither know nor care.
One of the people in this prompt is probably human, though it is certainly possible that they are not while the other one is clearly only half human.
This leads to all sorts of interesting questions. I think one of the more immediate questions is, what did they do that made it clear to the other person that they are not fully human?
Once you answer that question you are lead to a host of other questions, such as is one parent human and the other alien? Or are both of their parents also half human half alien? Have they ever been to another planet or were they born on earth? Are people in the story generally aware of the existence of aliens or is this something that just came up because of whatever the one person did.
Something else that is worth noting is the second person saying that the first is also half alien, half human, something they either do not know or do not want known. Of course it’s entirely possible it’s not true, but what is the truth of the matter?
How do you think this will play out? And do you think the first person really is part alien? And if they are, did they know and have been hiding it or is this news to them?