Below the Nether

Below the nether is a hard place to go. Currently, the bottom of the nether is just bedrock, like the overworld. However, this page suggests a new realm down there.

How to Access
To access it, a portal similar to the nether portal must be created, but on the bedrock layer and a 5x5 square instead of 4x5. It also has to be horizontal. Then, you pour lava into it to open, which creates a hole in the bedrock below. It will also create a red nether brick tower, going down from the hole so you can access. This will generate the Sub-Nether books below the hole.

Environment
The main biome of the Sub-Nether is mostly hollow, with large, open caves with stalactites on the ceiling and stalagmites on the floor, and tunnels connecting the caves. There are a few patches of blood slime clots scattered around. A tower of red nether brick is created when the portal is made, with stairs going down to the Sub-Nether surface level, where the tower will end. The blocks found there include:
 * Fleshstone.  A reddish, fleshy rock with veins in it.  Makes up most of the Sub-Nether.  When mined, drops fleshstone chunks which can be used to craft the block as well as smelted to produce fleshy chunks.
 * Blaze Rock.  Like Netherrack, it will burn constantly when out on fire.  The second most common block in the Sub-Nether.  Spawns in large gashes in the ground similar to ravines, and also in random patches.
 * Vein Block.  A fleshstone block with purplish veins running through it.  Transmits a redstone signal.  Spawns in an "on" state, powered by a center core.  Very common.
 * Blood Slime Clot.  A reddish, transparent block that blood slimes spawn on. Makes jump height slightly higher, but increases this effect greatly if placed on any non-nether or sub-nether block.

Mobs
The Sub-Nether is full of many horrifying mobs. They are all hard to see due to the Sub-Nether's dark environment, and are all very strong. In addition to all of these, zombie pigmen and regular zombies spawn down here too.

Undead Steve Health: 24 The undead Steve is a dangerous mob that appears as a red, fleshy version of the Steve player. It spawns fairly uncommonly in the Sub-Nether, and has a high chance to hold weapons, dealing 4 damage normally. They drop whatever item they are carrying, as well as 2-3 fleshy chunks and 1-3 iron nuggets. They have a chance to hold a shield, which they will use at random.

Mutilated Zombie Health: 38 Mutilated Zombies are a highly dangerous undead mob. They look like a zombie, but with their body and arms at random angles, as well as their head upside down and with another leg. They crawl along the ground, and attack the player quickly for 3 damage. Mutilated Zombies can also charge towards the player. They drop 3-6 fleshy chunks and 1-3 poisonous potatoes, as well as 3-12 gold ingots.

Flesh Golem Health: 50 These are uncommon but dangerous Sub-Nether mobs. Flesh Golems appear as a 4 block tall monster with 1 glowing eye made of what appears to be Fleshstone, with long misshapen arms and short legs. They walk towards their target and swing their arms in an arc, damaging anything in front of them. They also inflict slowness on their target, making them a formidable opponent. They drop 2-5 fleshstone, 2-4 rotten flesh, and 0-3 nether spines.

Blood Slime Health: 22 (big) 12 (medium) 8 (small) The Blood Slime is a mob that spawns only on Blood Slime Clots, and tends to stay around them unless chasing a player. When it dies, it splits into 2-3 medium size ones like other slimes. It jumps quickly and deals high knockback. It does 7 damage at large size, 6 damage at medium, and 5 damage at small. Its large size is slightly bigger than regular slimes, and its small is the size of medium slimes. It drops 1-2 blood clots at any size when killed, except small which drop 2-4.

Patchwork Beast Health: 280 The Patchwork Beast is a boss mob that spawns in the Sub-Nether. It is extremely rare, and only spawns in a large structure made of red nether brick and obsidian. It appears as a huge creature made of many creatures moulded together, with lots of limbs sticking out in random places with 6 main legs that it walks on. It has a large head at the front with a pointed snout, which acts as its main head. The Patchwork Beast attacks by swinging its front legs upwards like an iron golem, doing 6 damage. It can also summon blood slimes, which jump out of the floor. It can also shoot small projectiles out of its many side heads, which deal 4-8 splash damage depending on how far away you are. Additionally, it can bite with its front head, which has a 56% chance to inflict weakness. It drops 12-15 fleshstone, 5-8 blood clots, 3-4 nether spines, a lot of xp, and 1-2 patchwork claws.

Items
Fleshy Chunk. Obtained from any mob killed in the Sub-Nether or from smelting Fleshstone. It can be eaten, which restores 6 hunger but prevents the player from eating for the next 2 minutes.

Blood Clot. Obtained from breaking Blood Slime Clot blocks. It can be used to craft blood slime clots, and brewed to make leech potions which, when consumed temporarily adds 1 health point for every mob you damage in an attack.

Nether Spine. Can be loaded into a crossbow, and will deal much more damage than an arrow when shot. It also will stick in its target for 1 minute and 45 seconds, which increases damage they take by 12% as well as an additional 5% per extra spike. If their target moves up and down a lot, the spike will fall out. These don't work on the Patchwork Beast.

Vein Block in Redstone
The Vein Block has unique properties that make it useful in redstone. It can transmit a signal for 22 blocks at full strength, but then quickly fades to off after 2 blocks. It will only power redstone or vein blocks that it is facing towards or are facing towards it. If 2 vein blocks are facing towards each other, they will emit a strong redstone signal. When active, vein blocks have a pulse effect.