A mob farm is a structure in Minecraft that is used to spawn and kill mobs, which can then be used to collect their drops. Mob farms can be built in a variety of different ways, but the most efficient design for a mob farm in the mountains in Bedrock Edition 1.21 is a water stream design.
Water stream mob farms work by using a stream of water to push mobs into a central location, where they can be killed by a variety of methods. The most common method is to use a sword or axe to kill the mobs, but other methods such as lava or suffocation can also be used.
