Yes- there have been many confrontations of people having an earth experience and those we call aliens.
Firstly, I don't like to use the word alien! These beings are earthlings and for the most part, are not extraterrestrials; but that is another story that I have written about in many of my articles!
All aliens look human or humanoid. Some aliens look exactly like we on the earth look and some are disguised to look like us or, are slim possessing no body fat, no hair, and eyes designed to withstand the pressures associated with flying in high speed craft. However an alien might have looked, at one time like they were completely human, just like those here on the earth. The degree of technology possessed by an alien race determines how they look. Strangely enough, the most technologically advanced aliens look human!
Some of the encounters that many earth people have had, have been not with beings at all, but with machines that look somewhat human. I refer to these machines as surrogates.
Darwin's theory is not correct! We did not evolve from apes but rather as a specific being capable of a specific function. It is true we somewhat resemble these bipeds but close- yields us no cigar! Apes have their own specific function as do all creatures. Granted we have evolved physically; however, genetically we have always been human.
Best of luck on your journey-