Nether Reactor

The Nether Reactor is a structure built using a Nether Reactor Core - a block.

Crafting
Crafting the Nether Reactor Core requires three diamonds and six iron ingots.

Nether Reactor
The Nether Reactor is built with a nether reactor core, 4 gold blocks, and 14 cobblestone, arranged in the following configuration:

Top layer:

Middle layer:

Bottom layer:

When the Nether Reactor is built and the core activated (by clicking), it generates a room of Obsidian (7x17x17) with some openings, around the reactor called a "Nether Spire" (unofficial name). The blocks that make up the reactor, excluding the core, will turn into a new block called Glowing Obsidian, and it will start spawning various items and blocks, such as Gold, Melon Seeds, Paintings, Glowstone Dust, Doors, Mushrooms, Bones, Cacti, Arrows, Feathers, Bowls, Sugar Cane etc., as well as Zombie Pigmen. After it burns out, there will be a massive obsidian structure with multiple floors. But they are empty other than the bottom one. The core is still there, and is reusable. When the reactor is active, the core's texture will change to red, and after it burns out, it will change to a blackened texture.

The Nether Reactor only lasts around 45 seconds. During the 45 seconds the Reactor is active, it is difficult to escape the room, as it is all obsidian. Once the Nether Reactor has deactivated itself, the time sets to nighttime, so left over items in the room can despawn.

Bugs

 * Building the reactor at high elevation will prevent the reactor from being activated.

Trivia

 * The Reactor does not function in Creative mode; this is intended.
 * The reactor's structure was originally iron and gold blocks rather than cobblestone and gold, but this was changed due to its cost and the fact that the reactor turns into obsidian except the core.
 * You can not build the reactor partially or entirely in water.
 * You can quickly mine some or all of the materials out of the reactor after activation and it will still function, this way you can recycle the expensive Gold Blocks. Another alternative method is to simply have a friend help mine the blocks right after activation. (You should be able with a partner mine all four good blocks with diamond pickaxes before they turn to obsidian.)