My research specialisation is UFOs. By looking at UFO history you can easily see that "aliens" were most likely humans in costumes. The historical aliens are laughably absurd by today's more sophisticated Hollywood standards. See pics.
Normally the debate about a person encountering the strange revolves around either; 1) the witness lied or 2) the witness did not lie. No one ever asks, did the"alien"/"bigfoot" lie?
If "aliens" are humans pretending, as UFO history seems to show, how much easier to pretend to be a ape while wearing a fairly simple costume?
The next question is why? The answer is to deflect blame for abductions into research that wastes time and misdirects efforts. It is a variation of a false flag.
But why? Illegal human experimentation. Evidence? Alien abduction reports report often the medical table, medical procedure type scenarios. If we then add they are actually humans. Then human illegal classified medical experiments is the answer. We know this is possible because of MKULTRA being exposed. You might recall that most of MKULTRA documents were destroyed. Therefore we know a small fraction of the total abuses.
Now add in that MKULTRA experiencer Cathie O'Brien and US politicion John DeCamp both mention alien abductions as a trauma base for MKULTRA. See pic5 it has a link to references at the bottom.
Putting this all together it is more likely humans act as mythological creatures to abuse other humans.
If bigfoot was real we would find bigfoot bones. People prefer to believe a titillating fantasy rather than sinister truth. This misdirection has probably happened for thousands of years.