Shulker

Shulkers are box-shaped hostile mobs found in end cities. They hide in their shell to blend in with surrounding purpur blocks and guard the city's various treasures.

Spawning
Shulkers spawn during the generation of end cities, which are located on the outer islands of the End. They usually spawn on the walls of the city and on end ships. They don't despawn naturally, even in Peaceful difficulty, and once killed, they don't respawn unless spawners are used.

Drops
$$, shulkers drop 0-1 shulker shells. The maximum can be increased by 1 per level of Looting, which is 0-4 shells with Looting III.

$$, shulkers have a 50% chance of dropping a shulker shell when killed. This is increased by 6.25% per level of Looting, for a maximum of 68.75% with Looting III.

Shulkers also drop when killed by a player or a tamed wolf.

Behavior
The shell of the mob looks similar to a purpur block, blending in relatively easily to its surroundings. Inside the shell of the mob is a small yellow head with two eyes. Shulkers are uncolored by default when using spawn eggs, while white is the default when using or spawners. Spawning shulkers with other colors can be done using the command, as detailed below.

Shulkers generally remain stationary, attached to an adjacent solid block. However, if the block the shulker occupies becomes something other than air or the shulker finds itself not adjacent to any solid block, or the shell cannot open, it attempts to teleport (5 attempts per tick) to an air block within a 17×17×17 cuboid centered on the shulker that is adjacent to a solid block. If it finds no solid blocks to teleport onto (like when in the Void) it does not move.

Shulkers occasionally open their shell for 1–3 seconds to peer outside. When a target comes within about 16 blocks, it opens fully and shoots guided projectiles that follow the player, moving only along the X, Y, or Z axes and leaving trails of white particles. The projectiles can be destroyed by attacking them or blocked with a shield. If the projectile hits an entity, it does of damage and inflicts the Levitation status effect for 10 seconds. (Levitation has no effect underwater, or on players in boats.) The shulker continues firing every 1–5.5 seconds while the target remains in range. If the shulker's target dies with projectiles still in flight, they fall to the ground.

When its shell is closed, a shulker has armor points and deflects arrows. When the shell opens, it loses this natural armor and takes damage as normal. When at less than half health, a shulker has a 25% chance of teleporting (as described above) after taking damage. When a shulker is attacked, other shulkers in the area target the attacker as well.

Shulkers don't take burning damage from lava or fire, but they drown in lava. They teleport when touched by water.

In Peaceful difficulty, shulkers exist within the world, but do not attack, like vindicators and evokers.

Shulkers are treated differently than true blocks. For example, mobs are unable to pathfind around or jump over them, and falling on them from a height does not produce particles. Their spawn egg also does not destroy blocks such as grass.

Shulkers can be hooked by a fishing rod. However, they cannot be reeled.

$$, they apply Levitation II instead of I.

Dyeing
$$, shulkers can be dyed in a similar fashion to sheep. a dye on a shulker gives it the color of the dye.

Transportation


Shulkers can be moved by boats or minecarts; pushing a boat/cart into a shulker causes it to board. In a boat, the shulker retains the orientation it had before it was put in the boat. For example, if a shulker is attached to the ceiling: it is possible to build a platform adjacent to the shulker and slide a boat under it, at which point the shulker moves into the boat but appears upside-down. A boat's sides block some of a shulkers projectiles (more if it is upside-down).

A shulker pushed through the exit portal gets transported to the origin in the Overworld. Since shulkers teleport when not adjacent to a solid block they must be pushed down the central pillar of the exit portal with a piston.

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

Shulker bullet
A shulker bullet is a guided projectile that is shot from shulkers, and they follow the targeted entity along the X, Y, or Z axis and leave trails of white particles. A shulker bullet that hits a mob or player deals damage and affects them with levitation for ten seconds.

The shulker's projectiles also have entity data that control its movement.

The bullet can be destroyed by hitting it with any item, shooting it with an arrow, or blocking it with a shield. It explodes upon contact with a block. The explosion does not destroy any blocks and does not damage nearby mobs or players.

Trivia

 * Originally, shulkers were going to camouflage with a nearby block (shulkers next to purpur would look like purpur, and shulkers next to end stone would look like end stone). However, Jeb decided this was too difficult to code, so instead, shulkers were just purple mobs that would open and shoot.
 * The word "shulker" is a portmanteau (combination of multiple words) of "shell lurker".
 * All shulker named 'Dinnerbone' or 'Grumm', the mob flips upside-down, revealing a spiral pattern on the base. This appears to also lift the shulker by the same height as a pressure plate.
 * Shulkers can attack each other, in which case they shoot fully guided bullets at each other, but are unaffected by levitation when hit. The normal teleportation habits apply during shulker vs. shulker battles.
 * By using commands, they can be made to be part of a team to attack other teams and can be used as defense mobs. In that case, it doesn't attack its teammates but targets most hostile mobs without provocation.
 * Walking toward a shulker at the same level as the player's head pushes the player down to the one-block crawling position if there is space beneath.
 * If given the invisibility effect, only the shulker's shell becomes invisible. This is different to most other mobs such as armored mobs and saddled pigs, where the living part of the mob turns invisible with the outer areas remaining visible.
 * In the game's texture files, the shulker bullet is named "spark.png".
 * If a creeper has been hit by a shulker bullet and has the Levitation effect, it leaves a lingering levitation cloud where it explodes.
 * Gravity blocks glitch when on top of a shulker. (Sand on top of a extended shulker is higher than sand on one block but the sand is solid.)