There is no shortage of alien conspiracy theory out there from UFO crashes at Roswell to humans being the result of a giant alien experiment.
Depending on who you speak to, Aliens are either watching us, were directly involved in creating us or are in communication with our World leaders who keep it hushed up to stop panic spreading but the most widely believed theories show that aliens are out there somewhere doing something.
One theory hinges on the presence of 'junk' DNA of unknown function in our bodies which shows aliens tinkered with our ancestors DNA long ago or created them to begin with which serves as a kind of trademark to show that we are the creation of extraterrestrial life forms.
Another theory is that ancient aliens influenced human life in the past. The ancient aliens were directly involved in the evolution of primates, including humans. It has been suggested that they helped in the development of human cultures, technologies and even religion.
An opposite conspiracy theory is that aliens generally avoid making their presence known to humanity, or avoid exerting an influence on development, preferring to observe us using equipment located on Earth or elsewhere in the Solar System and on occasion throw us a curve-ball such as an earthquake or warming climate to see how we cope and evolve.