system
Given the following post, respond as if you're commenting on Reddit:
human
[Life] How would the alien lifeform be such a dangerous threat to Earth?

They didn't show anything about it reproducing and the only real dangers seemed to be it's durability and ability to consume matter and grow in size. So would it become some Godzilla sized lifeform and grow indefinitely? 

I was also wondering why dangerous alien lifeforms always seem to incorporate tentacles as their primary weapons, why is that? Think of Sentinels in The Matrix (not alien but still), Aliens and their tails, etc. Is it because multiple appendages are superior to less?
gpt
>I was also wondering why dangerous alien lifeforms always seem to incorporate tentacles as their primary weapons, why is that? Think of Sentinels in The Matrix (not alien but still), Aliens and their tails, etc. Is it because multiple appendages are superior to less?

Tentacles are simpler than limbs of endoskeletal or exoskeletal creatures. They are a relatively simple design, just a limb of muscle with no distinct joints.

Tails are a different matter. Because they are attached to a spine, they can be made to pack considerable velocity, while not being occupied with bearing the load of the creature - although kangaroos do stand on their tail while delivering a double kick.