The Nether



The Slip is part of the Minecraft Halloween Update. Not much is known about this underground world, which looks like hell; Only these things are sure:


 * Used for fast travel (More about this in the section below)


 * contrary to popular belief, Portals do not preserve momentum.


 * The only way to get in or out of it is by using portals, players can't just mine straight down and hit the Slip.


 * Special mob types (at least 2):
 * Ghasts - Hostile, flying, jellyfish-like monsters which shoot fireballs and are immune to fire. The fire balls will ignite everything around the impact zone, but not before making a small crater. Also, due to their preference to hover just outside your reach, the only reasonable way of killing them is with a bow and arrow.


 * Pigmen - Peaceful, humanoid creatures. They will attack if you hurt them, however. Since they drop meat, they could be considered a much more risky health source.


 * Special block types (at least 6):
 * Red Mossy Cobblestone - burns indefinitely, the main block forming the Slip.
 * "Australium" - a golden block that glows indefinitely (unlike Redstone, which only glows sometimes) . Australium is not the official name, it was nicknamed so by PCGamer.
 * Unnamed - a currently unnamed grey block resembling a creeper face. It properties are like mud, and as it suggests, you are slowed down whenever you walk atop this block.

Portals and Fast Travel
The portals are made by creating a 4x5 (2x3 on inside) door frame out of obsidian and then lighting the inside of the frame on fire. When you stand inside the portal for the first time, it will create a portal in its equivalent Hell area.

When re-entering the normal world, any distance covered in the hell world is multiplied by 16 times, effectively making the hell a fast travel zone that allows for greater distances to be covered in short amount of time in the normal world.

Naming
In the original announcement, Notch mentioned "a brand new Hell world". However, he's since stated that he doesn't want to offend anyone by using any religious connotations in the game. When the preview was sent out on 29 October 2010 to a couple of gaming websites, the new dimension was called the Slip. This is a placeholder name and might still change before the update is released.

Two possible names are:

The Nether: LordKarnov's Suggestion +  Notch's Reply

And

The Core: Benjabby's Suggestion + Notch's response