And it’s not aliens!
The small round scar on the upper part of your arm is very common if you are a 90s kid.
People who were born before 2000 A.D. are likely to have this very specific scar. It comes from a vaccine which was given to people in the form of an injection on the upper arm, preferably left. After the injection, children would get a swelling bulge pouring out yucky stuff for 2-3 days. The swelling wore off, and then after 2-4 weeks emerges again.
This time it turns into a water bubble and oozes liquid. Then it finally dries up and starts healing. The process leaves a scar which lasts you for your entire life.
And then small pox was effectively eradicated around the turn of the millennium. The vaccines were no longer made or administered, and that is why people who are born after the 90s no longer come with this distinctive scar.
Interesting isn’t it?