On a serious note, I would guess life forms capable of traveling billions of light years could easily make themselves appear as anything they want. Could be your boss, neighbor, or even your wife. I would guess it’s also possible for the minds of humans to be controlled remotely by highly advanced intelligence.
Oh, I’ve known for a long time that I’m the only human left, and everyone else is an alien masquerading as human. They’re pretty clever at it, but not quite clever enough to fool ME!
I suspect our cats…