Affects Version/s: Minecraft 1.13-pre1
Fix Version/s: Minecraft 1.13
Environment:Windows 7 64bit
- Launch a standard world
- Set time to 1600
- Set Difficulty to Hard
- Locate River using F3
- Clear out a 128 x 128 area from bedrock to skylight
- Cover in slabs (prevent mob spawning)
- Create small platform at Y=56-62 (ONLY PLACE BLOCK if Biome is RIVER)
- Move 24+ blocks away from small platform (vertically)
- Wait a bit
- Return to examine platform
Clear entities and wait using /kill @e[type=!player]
Verify mobs can spawn on platform by removing water.
Suggest to use the lowest FOV to view the spawning platform without having to move from the center of the spawn-proof area.
NOTE: Squid will spawn (when wet) and hostile mobs will spawn (when dry). But not Drowned.
If the platform is dry, standard mobs will spawn. If the area is filled with water, no hostile mobs will spawn.
Reducing all available spawn points to such a small area should force Minecraft's spawning system to produce a drowned, but only when the blocks are dry can a mob spawn.