Wither Skeleton

Wither skeletons are hostile mobs with stone swords found in fortresses.

Spawning
Wither skeletons spawn in fortresses at a light level of 7 or less, in groups of 5.

A wither skeleton spawn egg is found in the Creative inventory. This egg spawns only wither skeletons.

Spiders and cave spiders spawned in the Nether have a 0.8% chance of spawning as a wither jockey.

On normal difficulty or hard, the wither spawns 4 wither skeletons when below half health.
 * Wither

Drops
When killed, wither skeletons drop 0–2 s.

Wither skeletons have a $1/3$ chance to drop a single. The maximum amount of coal is increased by 1 per level of Looting. The chance of a wither skeleton not dropping any coal can be found using the formula. For example, Looting III gives a $1/3$ chance of not dropping any coal. All other amounts have an equal chance of occurring.

They also have a 2.5% chance to drop 1 when killed by the player or tamed wolf. Looting increases the chance by 1% per level (5.5% chance of a drop with Looting III). They always drop their skull if killed by a charged creeper.

They have an 8.5% chance of dropping their stone sword, which has a random durability and is always unenchanted.

They drop and an additional 1-3 per spawned equipment when killed by a player or tamed wolf.

Halloween
If a wither skeleton wearing a pumpkin or jack o'lantern is killed using a tool enchanted with Looting, there is a chance equivalent to the level of Looting used to drop the pumpkin or jack o'lantern, a maximum of a 3% chance of a drop.

On Halloween, wither skeletons have a 22.5% chance of spawning wearing a pumpkin and a 2.5% chance of spawning wearing a jack o'lantern.

Behavior
Wither skeletons wander when idle, but sprint at a player's walking speed when pursuing players, snow golems, baby turtles and iron golems within 16 blocks. When an entity is attacked, it is inflicted with the wither effect for 10 seconds in any difficulty, which turns the health bar black and decreases it by  every 2 seconds, similarly to poison. A wither doesn't attack them.

Up to 55% of wither skeletons pick up dropped swords and armor in normal or hard. Although they may, wither skeletons never take bows under any circumstances; if they hold a bow, they shoot flaming arrows even if their bows are unenchanted.

Wither skeletons are immune to poison, fire and the wither effect. They still seek for shade and water whereas under sunlight. Just like the skeletons, they sink in water, don't swim as they don't drown.

Data values
Wither skeletons have entity data associated with them that contain various properties of the mob.

Trivia

 * If a wither skeleton is wielding a bow (which can be spawned with ), it uses it like an ordinary skeleton, but the arrows it shoots are always flaming, regardless of enchantments.
 * Like other skeleton variants, wither skeletons do not know how to use a crossbow, despite the same using method as a bow.
 * Wither skeletons run from wolves like normal skeletons do.