I saw this movie in 2007, i remember only 2 scenes, it was a high budget zombie invasion kind of movie, but creatures were different, in one scene a girl changes with octopus like tentacles as her legs and throws some brown fish kind of things, who follows the target and changes them too, and this girl changing thing happens in front of hero, who is 20 something, in other scene a baseball player is alone in the stadium surrounded by zombie creatures fighting alone. Its not slither.