User blog comment:Lord Dalek/Who is the worst movie villian (alien)?/@comment-1705775-20120616024417

Blob is similar to The Stuff - though I personally find the Stuff even more malevolent.. the Stuff doesn't just eat you.. it eats you from *inside* and controls your mind beforehand.. forcing you to feed other people the Stuff and basically spread the alien's control.

Of course many will say Xenomorphs are high ranking but they have suffered some villain decay over the years due to a new focus on action-horror rather (such as the Aliens versus Predator craze).

Although it is debatable I'd say Stephen King's IT is also high up there - along with Killer Klowns from Outer Space (though some would argue IT isn't an alien).

The Thing is also pretty scary and popularized the body-horror genre, still the most dangerous species in the universe is mankind.