Zombies are undead creatures that oppose Wario in the Wario Land series. They are tall, humanoid beings of gray or green colour and mainly appear in dark areas, such as caves, dark rooms or in cities when it is night. The head of the Zombie can be separated from the body and serves as its main weapon.
In Wario Land II, Zombies are seen as gray, motionless heads that lie on the ground in dark areas. When Wario approaches them, they will rise from the ground and throw their heads at Wario three times. If the heads hit Wario, he will be turned into Zombie Wario. Wario can make the Zombies disappear by touching their body when they are separated from the heads, but the Zombies will quickly respawn after that. The only way to defeat them permanently is to attack them while in zombie form.
The Zombies return in Wario Land 3, where they once again turn Wario into Zombie Wario. They are of green colour in this game and cannot be seen as skulls before they rise. They are also notably quicker than before and less predictable. To attack, they will throw their heads at Wario one time and then disappear to respawn once again after a while.
The Zombies can pass sources of light without problems, while Zombie Wario gets turned back to his original form when exposed to it.