The Yellow Eye
It's moving. Where is it going?
It must have evil intent. What else could such a souless amoeboid be capable of?
To devour the defenceless creatures around it. They're always hungry, aren't they?
Or maybe, looking at the other side of the coin of paranoia, it's actually super intelligent. Isn't that more threatening?
Galactic conquest is a Chess game and the Yellow Eye is the grand master. (The whole story would just collapse if we just shot it or kicked it to death.)
Surely it must be advanced if it can survive without an eye socket, brain and the rest of a body. On the other hand, it will never be able to put on sunglasses or wear a hat.
I say we lure them out into the desert, slowly, like a bird pretending to have a broken wing, and let the sun and the wind bring low the mighty alien invader.