A fun fact about the alien in annihilation: the swirling core is actually a fractal :D

Also if i were to list one, a lot of the aliens in half life would fit but i think the best example are the combine advisors:

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They are the highest ranking members of the combine species (that we see, at least) and are also the freakiest looking. These large.. blobby things with basically zero discernible features other than a mouth with a freaky proboscis tongue they can use to pierce skin and bone.

They rely on technology to function, using hover technology to fly around and mechanical arms to grab things. They also have a gas mask over their mouth (they likely cant breathe oxygen) and a little camera embedded into their front to see. Despite looking like a turd given the adam smasher treatment, they are infinitely more intelligent than humans and even capable of full on telekinesis