Hello! Today, I've remade an old edition from Minecraft Pocket Edition, the Nether Reactor Core! It basically generates a castle with Zombie Pigmen and loot inside!

Click here for the command!

Crafting:
Nether Reactor Core - Iron Block + Diamond + Gold Ingot
Revived Nether Reactor Core - Damaged Nether Reactor Core + Diamond Block
All recipes are floor crafting

Tutorial:
To activate a Nether Reactor Core, first you must build the structure in
the image above. You see that diamond block? That is the Nether Reactor
Core. And if its hard to see, there is cobblestone underneath it. In total, you
will need fourteen cobblestone and four gold, along with a Nether Reactor
Core. Make sure you place the Nether Reactor Core last. After building the
structure, to activate the reactor, you will need to throw a diamond sword at
the Nether Reactor Core. You will get the sword back, and the process will begin.
The Nether Reactor Core will become damaged and will need reviving if
you want to use it again. You will see a massive netherrack castle appear, which
will take up a lot of land, so you might want to consider doing this away from
any buildings. Inside the castle, Zombie Pigmen will spawn, and so will five
different nether related items.

Credits:
By Code202

Notes:
For 1.9