What have people that saw space aliens say they look like?

Hello am 12 years old and this is what I have to say. People that say they have seen aliens say they look short and gray. They call them the Gray's also say men in black (not the movie) that never talk are aliens. How I know this is because I did a research project on aliens. Still no matter what they say we will never know for sure unless with see a alien with are own two eyes.