Wither

The Wither is a floating three-headed mob with a skeletal appearance. It is the second boss mob introduced in Minecraft.

Spawning
A Wither can only be spawned in game using methods similar to spawning utility mobs. By placing soul sand in a T shape (as shown in the image), and putting 3 Wither Skeleton skulls on top of each three upper blocks, the Wither can be created. Similar to all utility mobs, a Wither cannot be created by pistons. Also, the last block placed must be one of the three Wither Skeleton heads; it will not spawn if the final component placed is soul sand.

When spawned, the Wither will temporarily flash blue and grow larger in size as its health bar fills from half to full. While in this state, the Wither cannot move or attack and is immune to all damage. When this state ends, the Wither will create a very large explosion centered on itself, destroying nearby blocks. This explosion does not damage itself, but it will damage any nearby mobs. It is recommended for the player to walk away from the Wither at this state to avoid the explosion and to prepare for battle.

A ghastly sound is played when the explosion occurs. This sound is not centered around the Wither, instead it can be heard equally from all areas of the map.

Getting the necessary resources
It can be troublesome to find everything you need to spawn a Wither.

Getting Soul Sand isn't too difficult once the player manages to enter the Nether. It is extremely common, plentiful, and very easy to collect.

Obtaining three Wither Skeleton heads is the tricky part. A few things to know:


 * Wither Skeletons only spawn in Nether Fortresses, and finding one of these involves getting somewhat lucky. Maximize your Brightness and Render Distance (in Options), and occasionally stop to peer into the distance for the large, straight columns and bridges that indicate a Nether Fortress.  Nether Fortresses spawn every few hundred meters along North-South lines, so after checking one North-South line for a few hundred meters and seeing nothing, move East or West and begin scanning North-South again.
 * Nether Fortresses are dangerous places, especially for poorly equipped players. The combination of numerous Blazes and regular Skeletons, along with the Ghasts that may opt to bombard you at any given time---all of them ranged attackers---can be deadly.  The Wither Skeletons themselves inflict the Wither effect, which is a poison that can kill you---and will, if it hits while you are at medium-to-low health.  Prepare with Iron Armor, preferably enchanted, a Sword and---most importantly---a Bow with a steady supply of Arrows.
 * Once you kill a Blaze or two and receive your first Blaze Rod, and once you find a source of Nether Wart (look near the bottoms of the Nether Fortress's interior staircases), return to the Overworld and craft yourself a Brewing Stand, then a few Potions of Fire Resistance. Their 8-minute duration makes them a worthy potion for Nether Fortress raids.
 * Wither Skeletons are dangerous foes, but they cannot pass through a two-block-high doorway. You can use this to your advantage, but it may hinder your efforts to kill enough of them, quickly enough, to account for the final problem:
 * Wither Skeletons don't spawn especially frequently, will drop its skull only 2.5% of the time, and you need three of them (an average of 120 Wither Skeleton kills). To reduce the required grinding:
 * A Sword with Looting Enchantment improves the odds that a Wither Skeleton will drop its skull.
 * While time consuming, you can mine the walls to expand the floor space, giving Wither Skeletons more space to spawn.
 * Some Nether Fortresses are better than others for spotting the Wither Skeletons that do spawn. Nether Fortresses with plenty of bridges and columns that are open to the Nether give you much better visibility, allowing you to spot Wither Skeletons further away (they don't spawn very frequently), but you will have to contend with a barrage of Ghast attacks.  Conversely, a more sheltered Fortress comprised of hallways would protect you from above, but those same walls reduce your chances of spotting the Wither Skeletons that spawn.
 * If you'd prefer a different Nether Fortress, you can find one: Nether Fortresses typically appear on North/South lines, so moving in either of those directions should bring you to another.

Behavior
The Wither is hostile to the player and all mobs except undead mobs (skeletons, zombies, Zombie Pigmen, Wither Skeletons and other Withers). When provoked by a skeleton or another Wither, they will only remain hostile toward each other for a moment before returning to friendly status. If spawned in the End, it will prefer to attack any nearby Endermen, but will attempt to pursue and attack the Ender Dragon if there are no nearby targets.

The Wither can move very quickly. Upon noticing a mob, the Wither attacks them with a projectile called the “Wither Skull”. Wither Skulls move slowly and inflict a status effect called "Wither" on Normal and Hard difficulties. This effect is similar to poison, except that it can kill the player and turns the health bar black, making it difficult to tell at a glance how many hearts are still full. Although some may consider this cheating, an easy way to counter this issue, it is possible to modify the withering hearts texture to something that stands out better.

Each head fires individually, allowing a Wither to attack up to three different mobs at the same time. Withers need at least 5 block high airspace to fit, but as of snapshot 12w41b, they can no longer be trapped (and suffocated) in smaller rooms. Every few seconds, the Wither will break any block that comes into contact with it, except bedrock and end portal frame.

The Wither has an ability to destroy blocks, similar to the Ender Dragon's ability. When near any block that can be destroyed by a player, it will produce an audible smashing sound. For example, this could happen by having the Wither on one side of a wall, and the player on the other, so it would have to make a path through the wall to attack. The Wither will then instantly destroy a 3x3 hole in the wall to pass through it. The Wither also destroys a 3x3x4 space around itself 20 game ticks (1s) after being harmed.

The Wither's boss health bar is only shown when a player is looking in a direction of a Wither, and it can also be seen through walls when the player is looking in the Wither's direction. When reaching half health, the Wither will gain the "Wither Armor" effect, which makes it immune to arrows and potions, as well as having a visual effect surrounding it, similar to that of a Charged Creeper. While in this state, the Wither will only fly if angered. If calm, it simply hovers and is unable to jump up 1 block. When angered by the player, the Wither will fly at the same height as the player. Like other undead mobs (zombies, skeletons, etc.), the Wither is harmed by Potions of Healing and healed by Potions of Harming. It also regenerates over time ( every 20 ticks (1 second)).

In certain instances, the Wither has been seen to seemingly "eat" torches that have been placed by the player. A loud bite sound will play, and the light provided by the torch will disappear. Torches are not recovered once the Wither is killed.

Wither Skull


The Wither shoots Wither Skulls, which look like extra heads of itself launched as projectiles and it can keep up a fairly constant barrage of them. Upon contact, a Wither Skull will explode, although with a blast radius much smaller than that of TNT or a Creeper. If the explosion of a Wither Skull damages a mob or a player on Normal or Hard difficulty, it inflicts the wither effect, draining their health and turning their hearts black. If the skull hits a mob or player directly, it will also heal the Wither for health. There are two types of Wither Skulls: a fast moving black one, and a slow moving blue one. Both have an explosion power of 1, the same as Ghast fireballs; however, the blue skull has special properties.

The black Wither Skull has a normal blast, which cannot break blocks with a blast resistance above 20. Thus, cobblestone and other Ghast-proof blocks will resist this blast. The blue Wither Skull is shot only if the difficulty is set to normal or above, when the Wither is idle, meaning the player is not within its aggro range. Although it nominally has the same explosion strength as the black Skull, it treats all blocks (except bedrock and End Portal frame) as having a blast resistance of no more than 4. This makes it much more destructive to the terrain, and lets the Wither blast away obsidian traps or shelters from a distance. The wither can even unintentionally blast at faraway objects with the Blue, because if it misses, it will continue going until it hits a target, and may go on forever. A Blue may be seen later if it flies into an unrendered chunk, and that chunk is entered by the player after killing the Wither.

Combat
Because the Wither inflicts a great deal of damage, the best equipment for combat is a diamond sword (Preferably enchanted with Smite. The best sword for the fight is one enchanted with Smite V and Knockback II) Instant Health II Splash Potions, Strength II Potions, one or two enchanted gold apples, a Bow (Preferably enchanted with Power, the best bow for the fight would be Power IV or V, Punch II, and Infinity I) and Diamond Armor (Protection IV protects from the withering effects. The 'Thorns' enchantment may also be an advantage, but it is expensive and not as important as proper protection). Make sure to bring about a stack or two of arrows if you don't have the Infinity enchantment. Fire enchants do not work on the Wither. Smite is better than Sharpness, but a high level Sharpness should be good enough.

Bringing or summoning allies (Wolves, Snow Golems and Iron Golems) may or may not be advantageous: on one hand, they provide a diversion and will cause damage to the Wither: on the other hand, they may die easily because of the explosions and get affected by the Withering effect, healing the boss far more than they damage him. If you create the Wither in a small and completely enclosed underground area that isn't too large (three blocks tall), three Iron Golems are sufficient to kill one without aiding them. Spawn the Wither, and quickly run away as far as possible, putting a large distance between you and the Wither. Do not stand near the Wither when it is growing into its normal size. It will create a massive explosion when it is finished, much larger than that of TNT or a (charged) Creeper. When it is finished, walk back and shoot at the Wither, and occasionally use your Instant Health II Splash Potions and at some point, eat your Enchanted Gold Apples. When the Wither drops to 50% health, use your Strength II Potion and hit the Wither with your diamond sword until the Wither is defeated. This is a very effective way to beat the Wither, defeating it in less than five minutes with not too much struggle.

An extremely easy way of beating the Wither is to dig out a 10x10 by 3 tall room and spawn 30 or so Snow Golems. The Golems act as a target for the Wither, as well as attacking it. Accompany this with your best sword (preferably with the Smite enchantment), armor, and potions and you can beat him in under a minute taking little or no damage.

A tactic that is relatively easy to pull off is to dig down near bedrock, and dig a long 1x2 tunnel (Longer than 30 blocks). At the end of the tunnel, construct a small room. Spawn the Wither in this room, then run back into the tunnel. Occasionally pop out and shoot an arrow or two at the Wither. As the Wither crunches its way towards you, just walk backwards through the tunnel. Once the Wither has reached its "Armor" stage, jump out and begin hitting it with a diamond sword. As long as you frequently throw down splash potions of instant healing, you should be able to survive even with iron armor. A somewhat more complicated yet very enjoyable variant of this tunnel strategy (doubly so when you manage to kill the Wither using it) is to rig the tunnel you constructed with TNT. You could, for instance, build a tunnel as illustrated by the figure below; the idea behind this is that you can anticipate when the boss will crunch his way to a point sufficiently close to a pair of TNT blocks you've placed, and if you're accurate, you can have the TNT explode at that very instant, dealing a lot of damage. Be sure not to place the first pair of TNT right next to the room in which you will spawn the Wither, as the initial explosion would just destroy these. The drawbacks of this strategy are that it can be difficult to tell when to pull the levers; if you're too fast, the TNT will not have the desired effect. If you're too slow, the Wither will simply destroy the TNT prior to its detonation. In addition, you might need a lot of TNT to completely kill the Wither, and thus you'll have to dig out a long tunnel. Therefore it is strongly advised that you still use a bow (and a sword when the "Armor" stage has been reached) in the sections of the tunnel where there's no TNT to do the hard work. Also, if you don't have enough TNT, be sure to dig out an extra tunnel as an extension of the TNT-rigged one, so as to finish the Wither off with arrows/swords should needs be.

'''A simple TNT-rigged tunnel. The arrow indicates the way you will be moving with the Wither in pursuit''' A more advanced tactic that is very rewarding would be to construct a cobblestone generator-powered grid above the player, spawn the Wither about 15 blocks away, and stand under the grid. The Wither will fly towards the player, but it would be kept at the edge of the grid, constantly being pushed back by the cobblestone which is generating faster than what the Wither can break. This allows the player to stand still and shoot the Wither without retaliation, until the Wither is at half health, where it will fly towards the player through the grid, allowing the player to easily kill the Wither with a sword. In addition to that, the player can rig dispensers about 15 blocks away to periodically shoot splash potions of health, which heal the player and damage the wither. This tactic is explained in greater detail in this video.

It is also possible to kill the wither with a fully automatic machine, requiring no combat from the player. The most conventional design suffocates the wither with a cobblestone generator, as demonstrated in this video or this video.

Trivia

 * The Wither is 4 blocks tall, 3 blocks wide, and 1 block thick, however it's collision box is only 4 blocks tall, 1 block wide, and 1 block thick.
 * If the Wither has nothing to shoot at, it will stay still, moving very rarely.
 * The Wither can be damaged by the explosions of its own projectiles.
 * Dying from the Wither effect has its own death message: [playername] withered away.
 * Withers are unaffected by fire and lava, similar to Nether mobs. The Wither will not take drowning damage if somehow submerged in water for too long.
 * The Wither will take block suffocation damage. After the first tick of damage, it will destroy the blocks suffocating it if mobGriefing is turned on.
 * The command will give the desired amount of mob eggs set to spawn a Wither, but nothing happens when the player attempts to use it.
 * There is a hint to creating the Wither. Sometimes, when a painting is placed, it spawns a painting showing the soul sand+ Wither skeleton formation in order to spawn a Wither.
 * It is possible to just walk forward constantly and the Wither's skulls won't hit the player, as it is constantly adapting its speed to its target.
 * The Wither Armor glows red when it gets hit.
 * The sky in the overworld will turn slightly reddish when you look at the Wither.
 * The Wither Skull explosions can even break obsidian. At its high blast resistance of 6000, it's a block known for its hardness and explosion resistance to TNT.
 * The only blocks the Wither cannot break are air, (due to its indestructibility) End Portal block, and bedrock (its blast resistance being 18,000,000 and hardness being -1), probably to prevent holes in the lowest bedrock layer which would give an access to the void.
 * The Wither drops 50 experience, only twice the max drop for the Magma Cube (25 exp), but far behind by the Ender Dragon.
 * The Looting enchantment does not affect the Wither's Nether Star drop.
 * The Wither attacks all living mobs, including living hostiles like Creepers, Spiders, Ghasts, Endermen, and the Ender Dragon.
 * Withers have more health than the Ender Dragon
 * Withers can destroy more blocks than the Ender Dragon can.
 * Unlike Ghast Fireballs, Wither Skulls cannot be hit or shot with an arrow to be redirected. If they’re shot with arrows, they will be explode on contact, destroying the skulls and arrow.
 * In many foreign language translations, Wither is translated to a portmanteau of "Skeleton" and "Cerberus". This is due to the fact that it has three heads.
 * The Wither can still see you when you are using the invisibility potion and will not turn invisible when hit by an invisibility potion.
 * Wither explosions are not affected by the "Deadening effect" that water has on TNT and creepers.
 * Because it is undead, Splash Potions of Healing will damage it, but Splash Potions of Harming will heal it.
 * What looks like the vertebral column of the Wither is not exactly centered relative to the other part of its body: it is shifted by a half pixel on its right side.
 * If the Wither is fighting passive mobs and an Iron Golem is present, the Wither will stop and start attacking the Iron Golem. Probably because the Iron Golem's purpose is to defend from hostile mobs.
 * In Spanish (España) the Wither will be called Eustaquio and its own kill message will be translated to "[playername] sufrio una witherhostia" (Translated as "[playername] got witherpounded"). It's yet unknown if it is a joke, or an oversight by Mojang.
 * Even though the Wither is constantly adapting its speed with the player, players on horses can outrun the Wither as of now.
 * Withers can be used to grief in multiplayer, summoning one near someone's house is sure to leave significant damage.
 * In the Minecraft 2.0 April fools joke, there was a pink version of the Wither.