The analysis team, which went over the lifeboat centimeter by centimeter, found no physical evidence of the creature you describe.
9 seconds sound clip from the Aliens (1986) movie soundboard.
You can hear this line at 00:11:58 in the Blu-ray version of the movie.
Quote context
[...]
- The lifeboat's flight recorder corroborates some elements of your account, in that...
- For reasons unknown, the Nostromo set down on LV-426, an unsurveyed planet at that time...
- It resumed its course and was subsequently set for self-destruct by you for reasons unknown.
- Not for reasons unknown. I told you.
- Good! That's because I blew it out of the goddamn air lock, like I said.
- Are there any species like this hostile organism on LV-426?
- No. It's a rock. No indigenous life.
- Did I.Q.'s just drop sharply while I was away?
[...]