Undead

Undead, by definition, refers to an entity that is physically dead, but still animate.

Classification[]

Within Minecraft, it refers to an in-game category of mobs that share the following characteristics:

Are damaged by Instant Health and healed by Instant Damage;
Are not affected by Regeneration and Poison;
Take extra damage from Smite;
Do not take drowning damage (husks and regular zombies turn into regular zombies and drowned, respectively);
Are not targeted by the wither.

Some (but not all) undead mobs also possess these characteristics:

Are hostile to the player;
Catch fire under sunlight.

List of mobs[]

Name	Behavior	Notes	Type
Chicken Jockey	Hostile	Baby zombie or variants riding a chicken.	Zombie
Drowned	Hostile Passive (if not touching water during daytime.)	Drowned are common underwater zombie variants that spawn in oceans and rivers. They can be created if a regular zombie enters water and it fails to keep its head above water for 30 seconds straight.	Zombie
Husk	Hostile	Husks are a variant of zombie that spawns in deserts and do not burn in sunlight. They can be turned into regular zombies if kept underwater for 30 seconds straight.	Zombie
Phantom	Hostile	Phantoms are flying monsters that spawn when the player has not slept 3 or more in-game days.	Phantom
Skeleton	Hostile	Skeletons are common ranged monsters that are equipped with bows. They can be destroyed by sunlight.	Skeleton
Skeleton Horse	Passive Hostile (as a trap)	The skeleton horses are a skeleton variant of the horse that sometimes spawns when lightning strikes.	Skeleton
Skeleton Horseman	Hostile	Skeletons riding skeleton horses.	Skeleton
Spider Jockey	Hostile	Skeletons or variants riding spiders or cave spiders.	Skeleton
Stray	Hostile	Strays are variants of skeletons that spawn only in frozen, ice, or snowy biomes. They can be created if a regular skeleton enters Powder Snow and fails to escape within 22 seconds straight.	Skeleton
Wither	Hostile/Boss	The wither is a boss mob that floats and shoots explosive skulls at players and mobs.	Skeleton
Wither Skeleton	Hostile	Wither skeletons are tall variants of skeletons found in nether fortresses.	Skeleton
Zoglin	Hostile	Zoglins are zombified variants of the hoglin created when a hoglin leaves the Nether.	Zombie
Zombie	Hostile	Zombies are common monsters that deal melee damage and attack in groups. They can be destroyed by sunlight and will turn into drowned if submerged for 30 seconds straight.	Zombie
Zombie Horse	Passive	A zombie horse is an unused zombified variant of the regular horse.	Zombie
Zombie Villager	Hostile	Zombie villagers are zombified variants of the villagers.	Zombie
Zombified Piglin	Neutral	Zombified piglins are zombie variants of piglins and piglin brutes that inhabit the Nether. They were originally called "Zombie Pigmen." Zombified piglins can be created if regular piglins or piglin brutes leave the Nether and fail to return quickly enough.	Zombie
Bogged	Hostile	Bogged are variants of skeletons that spawn only in Swamps and Mangrove Swamps. However, they can also spawn in the Trail Chambers from a Monster Spawner.	Skeleton

Trivia[]

Despite the giant being an oversized variant of the zombie, it's not considered an undead mob.
Despite their ghost-like appearance, ghasts are not considered an undead mob.^[1] However, they are never targeted deliberately by the Wither boss.