This tutorial seeks to teach you about ghost blocks: what they are, uses, and how to get rid of one.
Use at your own risk.
Ghost blocks are considered annoying to a lot of players, considering that they often appear in the worst possible places and times.
What They Are
Ghost blocks are blocks that are not supposed to be in a certain position, but they are. They occur when the client sees a block in a certain position, but the game does not. The ghost block that results can have interesting properties.
How To Create One
The most common ways to make a ghost block are also considered the most annoying and most random.
The first way involves making a tool that can instantly mine a certain type of block, and then start mining away that block. Eventually, there will be an air block that causes the player to jitter if it steps on it or suffocate if it is at head-level.
The second way involves a flying machine. Simply set up a system that uses observer blocks to power the flying machine, and let it fly. It will randomly deposit ghost blocks of the flying machine.
Uses
They are mainly used to annoy people and perform "magic tricks."
What They Do
Ghost blocks can be pushed around with pistons. This also means that a piston can push up to 12 in a row. Exceeding that will still allow the piston to extend, but the arm will replace the new ghost block.
If a ghost sand block is pushed off the edge of a cliff, it will not fall. However, it will still create particles showing that it is in mid-air.
If you stand on a ghost block, the server can kick you for "flying."
Confusion Trap
Using these tactics, you can build a ghost block generator that creates ghost diamonds, claiming that you built a "diamond machine." You then offer a player some of the diamonds. However, when the other player tries to mine the ghost diamonds, they will get nothing because according to the server/game, it doesn't exist.
This is where you can really confuse that player. Take some blocks that match the ghosts. Place them next to one of the ghost blocks. From your perspective, there will be a brief moment when the real block is next to the ghost, before the ghost is replaced by the real diamonds. From their perspective, nothing changed. You can then mine these diamonds and get the items. Hilarity and confusion ensues.
How To Get Rid of Them
There are a few ways to get rid of ghost blocks. The first involves right-clicking on the ghost block. If the player is holding a block, then the ghost block will be replaced by the block the player is holding.
The second solution, which is much simpler, is to reload the chunks. This can be done with F3+A, moving, or logging out and logging back in.