{
  "feature": "minecraft:disk_grass",
  "placement": [
    {
      "type": "minecraft:count",
      "count": 1
    },
    {
      "type": "minecraft:in_square"
    },
    {
      "type": "minecraft:heightmap",
      "heightmap": "OCEAN_FLOOR_WG"
    },
    {
      "type": "minecraft:offset",
      "x": 0,
      "y": -1,
      "z": 0
    },
    {
      "type": "minecraft:block_predicate_filter",
      "predicate": {
        "type": "minecraft:matching_blocks",
        "blocks": "minecraft:mud"
      }
    },
    {
      "type": "minecraft:biome"
    }
  ]
}