Magma Cube

"Few are as deadly as the Magma Cube locking sights on you. Get seen by this red and black horror and it bounces for you relentlessly, its springy body barely concealing a molten lava core that will fill your body with hot flamy pain. Friendly hugs are not advised."

- Tom Stone

Magma cubes are hostile mobs with dark red and black skin and red, orange and yellow eyes that can be found exclusively in the Nether. They are considered the Nether equivalent of slimes, with similar behaviors.

Spawning
Magma cubes spawn rarely everywhere in the Nether at all light levels, but their spawn rate is higher in nether fortresses.

Magma cubes require two vertical transparent blocks (e.g., air, signs, torches) to spawn in, with an opaque block underneath. The space they spawn in must also be clear of solid obstructions and liquids. Big magma cubes require a 3×2½×3 space to spawn, small magma cubes require a 3×2×3 space, and tiny magma cubes require a 1×2×1 space (or 1×1×1 if the upper block is not opaque).

If successfully spawned, Magma cube will spawn in group of 1-4.

Drops
Magma cubes drop when they die:
 * $1⁄4$ chance of dropping a single when they are small or big
 * The chances and amount can be increased with the Looting enchantment.

Behavior
Magma cubes move by hopping, which they will do each 40 to 120 ticks (2 to 6 seconds).

Magma cubes will search for a player (or, failing that, an iron golem) within 16 blocks (spherical) distance.
 * If no target found, they wait 40 to 120 ticks (2 to 6 seconds). Then they will change direction, by a random amount up to 57.30° (1 radian) left or right, jump, and repeat the process.
 * If a target is found, the delay before jumping will be $1⁄3$ as long (13 to 40 ticks), and the magma cube's direction will be set directly toward the target before jumping.

Like other Nether mobs, magma cubes cannot burn and are not slowed down or damaged by lava. Instead, it seems that they can swim upward extremely quickly in lava. They cannot be hurt from fall damage and since 1.13 they can swim, and won't drown in normal water (in previous versions they can't and will drown).

Magma cubes' jump height depends on their size. Their forward speed is twice that of most other mobs. They always make a distinct sound upon jumping up and landing, but no idle sounds.

When the player kills a magma cube and the cube's size is larger than 1, it will die and spawn 2-4 new magma cubes equivalent to its size divided by 2, rounding down. The new magma cubes will be ejected at high speed..

Unlike most other mobs, magma cubes have no pathfinding ability, meaning that they will not avoid falling off cliffs and cannot go around walls, even when they are chasing a player.

Combat
Magma cubes attack players by attempting to land on top of them, but can cause damage when the player touches them anywhere. This can make large cubes tricky to fight, as their jump rate is fairly random.

The health of a magma cube is size squared. The attack strength is size plus 2. The armor points is size tripled.

A magma cube's jump height and distance also depends on their size; a magma cube will jump a distance approximate to its length times 1.5, and a height equivalent to their size in blocks. This means that a size 4 magma cube will jump four blocks in height and move significantly quicker than a size 2 magma cube, which will jump two blocks in height, while a size 1 (tiny) will move at a very slow rate and jump one block in height.

When a magma cube is killed, it may split into 1 to 4 magma cubes of the smaller size, and will disappear like other mobs if the smallest size is killed.

Magma cubes also have an odd attack interval: their attack speed is twice that of other melee-combat mobs. Mobs like Endermen and silverfish attack at a rate of one hit per second, while magma cubes attack at a rate of two hits per second. Essentially, this means that a size 4 magma cube will deal six hearts of damage per second on normal difficulty, dealing three hearts every half-second.

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

Trivia

 * When a larger magma cube that has a name dies, the smaller magma cubes it spawns will have the same name.
 * A dying magma cube can still damage the player.