Find a zombie or skeleton dungeon. Mark the coordinates. This gives you infinite attempts.
Place water source blocks to push mobs from the spawner room toward your trap hole. Water flows 7 blocks – use that to your advantage. lovely craft piston trap achievement guide top
A sticky piston with a slime block launches a mob off a ledge into a pit of dripstone. The fall damage is credited to the piston’s action. Find a zombie or skeleton dungeon