Please help to find an horror movie

It was very weird:
Some friends were in a cabin in the woods and a guy showed up (or they found him, can't remember). They let him in. He had a lot of stinky gas problems, and he was sick to his stomach.
The guys let him go sleep, but noticed that his tum keeps getting bigger and bigger, like if he was pregnant with something.
It cut to the guy going to the toilet and spending a while there, and then the guys couldn't find him anywhere in the house so they assumed he was behind the closed bathroom door and broke it, finding the hole room covered in blood, and the sick guy sitting on the loo, obviously dead. When they tried to lift him, the camera cut to a bloody and torn anus, then to something moving in the toilet,
which one of the guys quickly closed. One of them sat on it to keep the creature contained, the second one went to look for something.
Also, this movie had shots of animals with weird marks on their heads, most commonly seen on deer and does.
Asked Aug 07, 2014
im not sure but maybe its aliens..
Answered Aug 10, 2014

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