Everybody knows how big of a sandbox Minecraft is, but this is taking it to the next level: somebody has built a complete 8-bit RISC processor in Minecraft, capable of running custom software:
Sammyuri has reportedly spent seven months constructing an enormous–and enormously complicated–computer processor that exists virtually within the Minecraft engine. Although another Minecraft mod allows players to run the Mario 64 engine within Minecraft, sammyuri’s creation, called the Chungus 2, exists on an entirely different scale. The Chungus 2, which is short for Computation Humongous Unconventional Number and Graphics Unit 2, may be the single largest and most complex processor built in Minecraft as of writing.
He even wrote an assembler so you can program it yourself.