I was asked about Men In Black, whom I've encountered and they are shadow people using technology to disguise themselves as humans. There are shadow people, shadow animals, shadow planets, shadow stars and shadow galaxies. I know because I've asked aliens I've encountered who and what the Men in Black are. Which to quote Ripley's, believe it or not...
Video I uploaded long ago.
"We would feel them because gravity would spread through the extra dimensions from shadow branes that we cannot see. There could be shadow galaxies, shadow stars and even shadow people." - Stephen Hawking
And this what Men in Black look like when they use technology to make themselves visible to us in our lower dimension in their true form not disguising themselves as humans:
That being stated, they're the only negative species I've encountered because they think like humans and are corrupt. They don't understand our culture, only bothering to study it in order to better disguise themselves as humans because they consider us inferior. There are species that are indifferent who see us as lab rat specimens coldly and scientifically, however they treat us as stock and have ethics regarding stewardship of it. There are also species that are benelovent here to help and protect us. The Men in Black are the only ones I've encountered which are unethical much like us.