One, our Martian friend is a carbon-based life form. Two, he breathes nitrogen. And three, the large cerebrum here indicates... telepathic potential.
14 seconds sound clip from the Mars Attacks! (1996) movie soundboard.
You can hear this line at 00:21:05 in the Blu-ray version of the movie.
Quote context
[...]
- Well, they're not gonna eat off the Van Buren china.
- Oh, look at that brain. He must be real smart.
- It's gross. Don't forget, Nathalie... that we will look equally gross to him.
- Whoa. He made the international sign of the doughnut.
- From the limited information available, I've made three extrapolations.
- You mean they can read our thoughts?
- What about their intentions? Are they a friendly people?
- The human race, on the other hand... is an aggressively dangerous species.
- Now, I suspect they have more to fear from us... than we from them.
[...]