diff --git a/worldedit-core/src/legacy/java/com/sk89q/worldedit/blocks/MobSpawnerBlock.java b/worldedit-core/src/legacy/java/com/sk89q/worldedit/blocks/MobSpawnerBlock.java
index 929354ab9..0420d0994 100644
--- a/worldedit-core/src/legacy/java/com/sk89q/worldedit/blocks/MobSpawnerBlock.java
+++ b/worldedit-core/src/legacy/java/com/sk89q/worldedit/blocks/MobSpawnerBlock.java
@@ -134,15 +134,29 @@ public class MobSpawnerBlock extends BaseBlock {
         values.put("MaxNearbyEntities", new ShortTag(maxNearbyEntities));
         values.put("RequiredPlayerRange", new ShortTag(requiredPlayerRange));
         if (spawnData == null) {
-            values.put("SpawnData", new CompoundTag(ImmutableMap.of("id", new StringTag(mobType))));
+            values.put(
+                    "SpawnData",
+                    new CompoundTag(ImmutableMap.of("entity", new CompoundTag(ImmutableMap.of("id", new StringTag(mobType)))))
+            );
         } else {
             values.put("SpawnData", new CompoundTag(spawnData.getValue()));
         }
         if (spawnPotentials == null) {
-            values.put("SpawnPotentials", new ListTag(CompoundTag.class, ImmutableList.of(
-                    new CompoundTag(ImmutableMap.of("Weight", new IntTag(1), "Entity",
-                            new CompoundTag(ImmutableMap.of("id", new StringTag(mobType)))
-                    )))));
+            values.put(
+                    "SpawnPotentials",
+                    new ListTag(
+                            CompoundTag.class,
+                            ImmutableList.of(new CompoundTag(ImmutableMap.of(
+                                    "weight",
+                                    new IntTag(1),
+                                    "data",
+                                    new CompoundTag(ImmutableMap.of(
+                                            "entity",
+                                            new CompoundTag(ImmutableMap.of("id", new StringTag(mobType)))
+                                    ))
+                            )))
+                    )
+            );
         } else {
             values.put("SpawnPotentials", new ListTag(CompoundTag.class, spawnPotentials.getValue()));
         }