To make a mob farm in Minecraft that automatically spawns and kills enemies, you'll need stone, trapdoors, chests, hoppers, slabs, and water.
CherionMC on MSNOpinion

How to Build a Mob Trap in Minecraft

This build creates a mob trap that collects drops automatically using redstone and water flow. It is efficient, compact, and ...
One of the major factors of the success that Minecraft has enjoyed is undoubtedly the massive replayability of the sandbox title. With new content periodically added to the game to keep things fresh, ...