A zombie walk is when a group of people get together and dress up like zombies. They put on gory makeup and fake blood to make themselves look like they are dead and have come back to life. Then, they walk around in a slow, clumsy manner as if they are zombies. It's like pretending to be in a zombie movie or TV show! People do this for fun, and often gather in a large group to walk around together, moaning and groaning like zombies. It's not real, though - they're just playing a game and having fun.