Oh, no doubt - there’s plenty of rules for zombies too. It’s just that you can’t apply real-world logic to a zombie apocalypse because the only way for one to be feasible is if we first accept a few impossible claims and don’t question them.

Zombies are dead by definition, so no heartbeat. They don’t get thirsty or hungry - they eat flesh but not to survive, it’s just instinct. They don’t freeze or overheat, they rot really slowly, they can’t communicate, run, climb, or swim. They can’t bleed out, suffocate, or be poisoned. The only way to kill one is by destroying the brain. Why? Well, because that’s the rules we all agreed on the moment we start seriously discussing zombies.