Experiences with off world beings for the most part may seem foreign to most humans on Earth.
They can be extremely terrifying and can cripple those even with the most stout heart.
Many people who have had contact with ET's will say this is so. The experiences are confusing, they are disorientating, and it is something beyond normal understanding.
There are also those ET experiences that are beautiful, they seem serene, intelligent and extraordinary.
The cosmic man from somewhere near Aldebaran.
So since we know they are here, WHAT are they doing here?
Well with each race, with each civilization or group that visits planet Earth, or is perhaps, somewhat 'residential' upon the surface- they each have their own AGENDA'S.
And naturally these agenda's are completely variable in their objectives.
A race of Gray's for example, have been known to carry out a specific hybridization agenda, which includes the perpetuation of their own species, creating new species and experimenting with genetic/biological tissue.
A race of the Reptilians come to Earth to pick up/drop off occupants because they are masters at cosmic navigation and understand routing interstellar maps for the vastness of the cosmos.
Another race of Reptilians lives beneath the Earth and are in fact native to the planet.
And ANOTHER Reptilian race comes to Earth purely for their own self serving desires and could not care less about humans.
ON a lighter note~ Other races come to spread messages of peace & love, and to aid in the evolution of human kind.
Some come to mine and excavate the Earth's minerals/metals and harvest the water.
Some come to observe and study the human race, the plants, the animals to generally just learn about us and our adaptation.
Some come study the sun and the affects that it has on the Earth.
Some come to check on humans, specifically humans that share the same DNA as them or are perhaps from the same star system as them.
Some just come to pass by- like tourists would travelling all over the world.
There are endless reasons of why ET's & Aliens are amongst us and those above are just a random few.