Buddy
The Dunne's ginger cat patiently watches everything without a care in the world as the couple's marriage collapses.
If only the cops had asked "Buddy" what had happened, this thriller would have been over 2 hours sooner.
And no, the cat didn't do it.
According to an article on the lead animal trainer Larry Payne--http://ihavecat.com/2015/03/23/cat-man-monday-larry-payne-the-man-behind-the-gone-girl-cat-s/--the cat's name is supposed to be Bleeker. The role was played by two cats: Boris and Krinkle.