I wanted to ask how do you call this, how do you create this and how do you set it to keep getting smaller or bigger?:
Minecraft Java.
This is a world border and you can increase it through achievements
As far as I know, it can't be made smaller
OK thanks
That is called worldborder
Have looked you can use the command: / worldborder add [number of blocks]
Here
This is called worldborder.
You can use the command / worldborder set [size] [time] to enlarge or reduce the worldborder within a certain time.
Before that you can determine the center with / worldborder center [coordinates].
With it you can set great game modes.
