The six-member crew of the International Space Station is tasked with studying a sample from Mars that may be the first proof of extra-terrestrial life, which proves more intelligent than ever expected.
This movie contains 43 potentially triggering events.
I found the rat being killed extremely upsetting. However it's clear its about to happen before it actually does, so you have time to look away/cover your screen.
Alien goes inside a person to kill them but not to possess and another to feed on them. Another person helps the alien in his obsession but is not implied that he is possessed by the alien.
The creature crawls into the mouth of a character. There is a very long and vivid choking scene before he begins to cough up blood, and eventually the creature crawls back out of him after he has died.