Quicksand that can replace dirt or grass

src/resources/assets/mmm/blockstates/materials/trap/swamp_pit.json

@@ -0,0 +1,5 @@
+{
+    "variants": {
+        "normal": { "model": "mmm:materials/trap/swamp_pit" }
+    }
+}

src/resources/assets/mmm/models/block/materials/trap/swamp_pit.json

@@ -0,0 +1,21 @@
+{
+    "parent": "minecraft:block/grass",
+    "textures": {
+        "particle": "minecraft:blocks/dirt",
+        "all": "mmm:blocks/materials/trap/swamp_pit"
+    } ,
+	"elements": [
+		{
+			"from": [ 0, 0, 0 ],
+            "to": [ 16, 16, 16 ],
+            "faces": {
+                "down":  { "uv": [ 0, 0, 16, 16 ], "texture": "#all", "cullface": "down", "tintindex": 0 },
+                "up":    { "uv": [ 0, 0, 16, 16 ], "texture": "#all",    "cullface": "up", "tintindex": 0 },
+                "north": { "uv": [ 0, 0, 16, 16 ], "texture": "#all",   "cullface": "north", "tintindex": 0 },
+                "south": { "uv": [ 0, 0, 16, 16 ], "texture": "#all",   "cullface": "south", "tintindex": 0 },
+                "west":  { "uv": [ 0, 0, 16, 16 ], "texture": "#all",   "cullface": "west", "tintindex": 0 },
+                "east":  { "uv": [ 0, 0, 16, 16 ], "texture": "#all",   "cullface": "east", "tintindex": 0 }
+            }
+        }
+	]
+}

src/resources/assets/mmm/models/item/materials/trap/swamp_pit.json

@@ -0,0 +1,3 @@
+{
+    "parent": "mmm:block/materials/trap/swamp_pit"
+}