Squid

Squids are common 8-armed passive mobs that spawn in water.

Spawning
Squids spawn in water between layers 46 and sea level, in groups of up to 4 in the world generation and can be found in any biome. After the world generation, they may still spawn in individuals and will only spawn in rivers, beach variants and ocean biomes.

Squid do not spawn anywhere if the world type is classic flat (due to the sea level for superflat worlds being at Y=0).

Unlike other passive mobs, squid may despawn over time.

Bedrock Edition
In Bedrock Edition, squids spawn only in all ocean and beach variants biomes. They also have a 5% chance to spawn as babies.

Drops
When killed, each squid will drop 1–3 ink sacs. They drop 1–3 experience when killed by a player or tamed wolf.

Behavior
Squids are always passive towards the player, akin to the other passive mobs found on land. They are not attracted to light and do not deliberately interact with the player. They also do not take an exact path of travel.

When a squid moves, its tentacles open and close, giving them an appearance of pushing themselves forward, which they will do slowly. Squids hover in place when first spawned into the world and wander around aimlessly, swimming up and down through each layer.

Squids suffocate to death if they are beached on land for too long. While on land, they do not move, and stay stationary until they suffocate. They can take fall damage and burn like any other land mob, but they cannot drown. When out of water, squids are extremely resistant to knockback.

Squids cannot swim in lava, even if given a Fire Resistance potion. They simply pass through the lava and behave as if on land.

Unlike other land-based mobs, squids can swim against a current and not get pushed by it.

Squirting ink
Squids produce a cloud of black ink particles and rapidly swim away in the opposite direction from the player/guardian when attacked. They also produce dark blue bubble particles when hit, which are exclusive to this mob.

Weakness
Guardians will attack squids in the same manner as they would a player, even if the squid is affected by invisibility.

Squids, being aquatic mobs, are affected by Impaling enchantment.

Data values
Squids have entity data associated with them that contain various properties of the mob. Their entity ID is.

Trivia

 * Hitting a squid underwater causes them to rise approximately $1⁄3$–$1⁄2$ a block.
 * Squids cannot be damaged by attacks to their tentacles.
 * Squids don't have a death animation.
 * Squids behave like some land mobs and attempt to ride a minecart, but this is not always useful as rails and water cannot occupy the same block.
 * Squids are the first passive mob to spawn at any light level, in water, and without grass.
 * Prior to 1.9, squids did not have any sound effects, and were the only mobs that had no sound effects.
 * The squid's idle sound is barely audible.