Dark-Room Creeper Tower in Minecraft

Build the lower platform at x=8..11, z=8..15, y=0, with the five hoppers and the chest shown. Place four lit campfires at x=9..10, z=9..10, y=1.

💡 Use zero-based coordinates. The x=10 hoppers face west into x=9; x=9 hoppers at z=9, 10 and 11 face south into the chest at (9, 0, 12). Start high above the ocean or comprehensively spawn-proof nearby terrain and caves. The landing pad and spawn room must both remain in loaded chunks; allow room above for the roof.

Build the 4x4 perimeter at x=8..11, z=8..11 from y=1 through y=25, leaving its central 2x2 column open.

💡 The interior x=9..10, z=9..10 must remain dry and unobstructed from the later gates to the campfires. Solid walls keep you out of creeper sight. Never add a viewing hole at the landing chamber.

Place four 8x8 pads at y=27: pair x=1..8 or 11..18 with z=1..8 or 11..18. Lay the cross-shaped canal floor at y=25.

💡 Each canal arm is two wide and eight long: x=9..10 with z=1..8 or 11..18, and z=9..10 with x=1..8 or 11..18. Leave the central 2x2 drop completely open. A two-block step between pad floors and canal floors gives mobs room to fall into the water.

Build the 20x20 outside wall ring at x=0, x=19, z=0 and z=19 from y=25 through y=29.

💡 No windows, permanent torches or light-emitting blocks belong in the spawning chamber. Keep temporary lighting while working and remove it before sealing. The campfires are far below the pads, so their block light cannot reach the spawn floor.

Place closed top-half trapdoors over all four pads at y=29, open trapdoors around the canal edges at y=27, and the 36 carpets at y=28.

💡 Closed ceiling trapdoors leave 1 13/16 blocks of clearance above pad surfaces. On each pad, use three carpet rows and three columns: coordinates 2, 5, 8 on north/west pads and 11, 14, 17 on south/east pads. Edge trapdoors occupy x=9 and 10 beside vertical canals, and z=9 and 10 beside horizontal canals; open them vertically against their adjacent pad edge. Keep every ceiling trapdoor closed.

Place four open fence gates at x=9..10, z=9..10, y=26, then add the eight canal water sources.

💡 Place sources at (9, 26, 1), (10, 26, 1), (9, 26, 18), (10, 26, 18), (1, 26, 9), (1, 26, 10), (18, 26, 9) and (18, 26, 10). Reuse two buckets with an outside infinite source. All gates must remain open and dry: they block water while letting mobs fall. Use temporary blocks to place the gates if needed, remove those supports and check that no water reaches the campfires.

Cover the complete 20x20 area at y=30 with solid blocks, then cover y=31 with bottom slabs.

💡 Remove temporary chamber lighting before sealing the last roof opening. Full walls and roof must block sky light; check for block light level zero on the pads. Remove temporary scaffolding and exterior spawnable ledges. Build in a biome that permits ordinary hostile mobs, with Easy, Normal or Hard difficulty and mob spawning enabled.