Visible crew/equipment: A giant lizard grabs hold of Mason with its very long tongue. Cables can be seen around the fake tongue which are both wrapped around Mason's left leg. (02:00:10)
Visible crew/equipment: A diary flies out of Mason's hand while they are on a raft because of Earth's magnetic field. You can see a wire attached to the left corner of the book. (01:43:55)
Answer: It's just an added sound effect that foreshadows an ominous event (the giant reptile) that is about to happen. It's not meant to be anything naturally occurring.
raywest ★