I'm not gonna say "MY AU!!" cause we don't know where marley came from, we don't know if he's infected or not, we just know that he's Marley Russell. (and cool looking)

You were exploring a lab that you were specifically told to not go in, it dosent matter, you snuck in anyway. you went into some cool room that caught your eye, and saw a robot dog thing, just staring at you.