Nether Reactor

The Nether Reactor is a built structure which, when activated, generates a room of obsidian (7x17x17) with some openings around the reactor called a "Nether Spire" (unofficial name). It also turns the reactor itself, excluding the core, into glowing obsidian. At this point the reactor will begin to spawn various blocks and items, as well as Zombie Pigmen.

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

Behavior
When the Nether Reactor is built and the core activated (by clicking), there will be a Client message that says, "Active!", and it generates a room of Obsidian (7x17x17) with some openings, around the reactor called a "Nether Spire" (unofficial name). It destroys any block that happens to be in the way of the room. 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. The blocks are: gold ingots, melon seeds, paintings, glowstone dust, doors, mushrooms, bones, cacti, arrows, sugar canes, bowls, beds, bows, and feathers, as well as Zombie Pigmen. After it burns out, there will be a massive obsidian structure with multiple floors. The bottom floor is hollow (all blocks inside other than the reactor are replaced with air), and the upper floors retain the blocks that were already there (air for an above-ground spire, dirt/stone/etc. for an underground spire). The core is still there, and is reusable. The used core is found in a 3x3 Obsidian box where the reactor was constructed. 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 about 5,10, or 15 seconds have passed, the time sets to nighttime, so left over items in the room can despawn once the Nether Reactor stops.

Bugs

 * If placed at bedrock, when the reaction occurs, it will remove the bedrock. Using this, one can access the Void in Survival mode.

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.
 * The air blocks in the pattern are not optional. This means you cannot build the reactor underwater unless you waterproof the air blocks in the pattern.
 * 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. If you're fast enough, you'll have time to mine all four gold blocks with a diamond pickaxe before they turn to obsidian.
 * If you construct the reactor near a world edge and activate it,you will see it turn night.
 * There is an elevation limit for the reactor, above which it cannot be activated.
 * If you want to hide the spire produced by the reaction, build the reactor deep underground.
 * If you want the spire not to get "blown up", you can break the active core.
 * Breaking glowing obsidian is the only way to get obsidian without a diamond pick.