Minecraft wiki entry for Music_disc_farming, associated text: You can also use boats to trap skeletons and creepers into place. Trapping a skeleton may prove difficult however since they cannot swim. With both a creeper and a skeleton in boats near to each other, you can swim between the boats and cause the skeleton to shoot the creeper. If you have enough armor and health, you can also enter the skeleton’s boat and move it closer to the creeper. OR You can get a boat to trap the creepers in it. Make sure there are skeletons nearby and get them close to the boat. Try to get the skeletons to shoot the creepers in the boat. Keep repeating the process until you get the discs you want. Do not put them in the same boat. If the skeleton shoots the creeper, the creeper may explode!