Squid

Squid are 8-armed mobs that spawn in water.

Spawning
Squid spawn in water between layers 46 and 62, and can be found in any biome.

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
Squid are always passive towards the player, akin to the other passive mobs found on land.

When moving about, the squid's tentacles open and close, giving them an appearance of pushing themselves forward. Squid hover in place when first spawned into the world and wander around aimlessly, swimming up and down through each layer. They are not attracted to light, and do not deliberately interact with the player. However, if attacked, squid will attempt to swim away from the player.

Squid suffocate 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 land mob, but, due to being aquatic they cannot drown.

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

Squid (unlike land-based mobs) can swim against a current and not get pushed by it.

Guardians
Guardians will attack squids in the same manner as they would a player, regardless of the squid having the Invisibility potion effect.

Trivia

 * Hitting a squid underwater causes them to rise approximately 1/3 to 1/2 a block.
 * Squid cannot be damaged by attacking their tentacles.
 * When out of water, squid are extremely resistant to knockback.
 * Squid 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.
 * Squid are the first passive mob that spawn at any light level, in water, and without grass.
 * When the world is loaded, all squid are aligned with the tentacles facing east.
 * Squid are one of the few silent mobs in Minecraft, along with Witches and Snow Golems.
 * In RC2, when Squid came out of the water and were hurt, they made the new player hurt sounds.
 * Squid and bats are the only passive animals that cannot breed; due to this, however, they will spawn randomly (similar to hostile mobs).
 * Squid, ocelots and bats are the only passive mobs that can despawn.