Zombies are hostile creatures exclusive for the GoatZ map. In tutorial world and after outbreak map, they deal damage to player's health icon.
There are 8 types of zombies.
Normal zombies, Spitting zombies and Goat zombies are the basic one, spawning from the start of outbreak. Normal zombies deal damage just by punching you, which most of the time isn't very effective, as zombies can't easily walk over obstacles. Spitting zombies, recognised by a bag with a hole on their heads, are most of the time trying to shoot the player with homing, green slime like projectiles, which deal a small amount of damage. Zombie goats, which can be any animal except elephant infected by the zombie plague, charge and chase the player, dealing a lot of damage, which makes them really dangerous.
After a few days, fireman goats/elephant zombies, as well as nude russians, will start to spawn. Fireman goats or infected elephants spit fire with thier trunk, but are not very effective, as they run slowly. Nude russian guys, running around censored and saying stuff like "I REPORT U!" are the strongest ones. This title comes from their infinite health, speed and steal ability. If they reach the player's goat, they steal his weapon, using it against him immediately, which often can lead to one shot death. The only effective way to get rid of them is by shooting them with heartbreaker weapon, as its projectile deletes the enemy. It is also possible to 'drown' them by leading them to any body of water.
The ghost versions of normal, spitting and elephant zombies will start to spawn even later. They have more health and deal more damage, in order to make the game harder.
To kill every type of zombies but russians, use weapons, headbutt/kick them, or have cars run over them. All enemies can also be thrown in sea or puddles as they can't swim.