You mean like Invasion of the Body Snatchers Jess. Thata is very possible given the technology Thomas espouses they possess.Just imagine if we had unexpected visitors disguised as humans, infiltrating our way of life until they fit in, they could overtake us and force us into hiding.
I would go to youtube and do a search for reptilians, they're already here and they have infiltrated most of our government departments posing as politicians.
No alien is going to invade or overtake us. We should rather beware of certain humans and their movements to force us into something.