It's true. If any aliens that are even bigger than ants would be possibly scarier than what the human mind can imagine. Why? Because if sentient aliens existed, their bodies basically wouldn't obey our laws.
Another thing to think about; Their cells formed radically different from ours. That means that their entire integrity would go against every law of nature that we obey solely for the fact that they formed galaxies away from us.
The fact that they would be completely different puts me off. I wouldn't want aliens to land on earth. They would possible forget something up completely and kill us all. Think of all the functions they could do that we can't even begin to think how the hell it would happen. They could release this giant floating ball from their stone-like skin and it makes a weird "ding" sound, and then everyone dies.
So the thought of what real aliens would be like is scary.
