diff --git a/patches/minecraft/net/minecraft/world/level/NaturalSpawner.java.patch b/patches/minecraft/net/minecraft/world/level/NaturalSpawner.java.patch
index 48dfcb86f8..f2bf5a1c65 100644
--- a/patches/minecraft/net/minecraft/world/level/NaturalSpawner.java.patch
+++ b/patches/minecraft/net/minecraft/world/level/NaturalSpawner.java.patch
@@ -69,7 +69,7 @@
                          entity.m_7678_(d0, (double)blockpos.m_123342_(), d1, p_151620_.nextFloat() * 360.0F, 0.0F);
                          if (entity instanceof Mob) {
                             Mob mob = (Mob)entity;
-+                        if (net.minecraftforge.common.ForgeHooks.canEntitySpawn(mob, p_151617_, d0, blockpos.m_123342_(), d1, null, MobSpawnType.CHUNK_GENERATION) == -1) continue;
++                           if (net.minecraftforge.common.ForgeHooks.canEntitySpawn(mob, p_151617_, d0, blockpos.m_123342_(), d1, null, MobSpawnType.CHUNK_GENERATION) == -1) continue;
                             if (mob.m_5545_(p_151617_, MobSpawnType.CHUNK_GENERATION) && mob.m_6914_(p_151617_)) {
                                spawngroupdata = mob.m_6518_(p_151617_, p_151617_.m_6436_(mob.m_142538_()), MobSpawnType.CHUNK_GENERATION, spawngroupdata, (CompoundTag)null);
                                p_151617_.m_47205_(mob);
diff --git a/patches/minecraft/net/minecraft/world/level/levelgen/feature/NetherFortressFeature.java.patch b/patches/minecraft/net/minecraft/world/level/levelgen/feature/NetherFortressFeature.java.patch
index b761735cdc..659dcb1570 100644
--- a/patches/minecraft/net/minecraft/world/level/levelgen/feature/NetherFortressFeature.java.patch
+++ b/patches/minecraft/net/minecraft/world/level/levelgen/feature/NetherFortressFeature.java.patch
@@ -1,14 +1,16 @@
 --- a/net/minecraft/world/level/levelgen/feature/NetherFortressFeature.java
 +++ b/net/minecraft/world/level/levelgen/feature/NetherFortressFeature.java
-@@ -33,8 +_,9 @@
+@@ -33,8 +_,11 @@
        return NetherFortressFeature.NetherBridgeStart::new;
     }
  
 -   public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142494_() {
 -      return f_66381_;
 +   @Override
-+   public List<MobSpawnSettings.SpawnerData> getDefaultSpawnList() {
-+      return f_66381_.m_146338_();
++   public List<MobSpawnSettings.SpawnerData> getDefaultSpawnList(net.minecraft.world.entity.MobCategory category) {
++      if (category == net.minecraft.world.entity.MobCategory.MONSTER)
++         return f_66381_.m_146338_();
++      return java.util.Collections.emptyList();
     }
  
     public static class NetherBridgeStart extends StructureStart<NoneFeatureConfiguration> {
diff --git a/patches/minecraft/net/minecraft/world/level/levelgen/feature/OceanMonumentFeature.java.patch b/patches/minecraft/net/minecraft/world/level/levelgen/feature/OceanMonumentFeature.java.patch
index 72aac312a7..cea7d68054 100644
--- a/patches/minecraft/net/minecraft/world/level/levelgen/feature/OceanMonumentFeature.java.patch
+++ b/patches/minecraft/net/minecraft/world/level/levelgen/feature/OceanMonumentFeature.java.patch
@@ -1,14 +1,16 @@
 --- a/net/minecraft/world/level/levelgen/feature/OceanMonumentFeature.java
 +++ b/net/minecraft/world/level/levelgen/feature/OceanMonumentFeature.java
-@@ -55,8 +_,9 @@
+@@ -55,8 +_,11 @@
        return OceanMonumentFeature.OceanMonumentStart::new;
     }
  
 -   public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142494_() {
 -      return f_66469_;
 +   @Override
-+   public java.util.List<MobSpawnSettings.SpawnerData> getDefaultSpawnList() {
-+      return f_66469_.m_146338_();
++   public java.util.List<MobSpawnSettings.SpawnerData> getDefaultSpawnList(net.minecraft.world.entity.MobCategory category) {
++      if (category == net.minecraft.world.entity.MobCategory.MONSTER)
++         return f_66469_.m_146338_();
++      return java.util.Collections.emptyList();
     }
  
     public static class OceanMonumentStart extends StructureStart<NoneFeatureConfiguration> {
diff --git a/patches/minecraft/net/minecraft/world/level/levelgen/feature/PillagerOutpostFeature.java.patch b/patches/minecraft/net/minecraft/world/level/levelgen/feature/PillagerOutpostFeature.java.patch
index 8af371083c..87022276f9 100644
--- a/patches/minecraft/net/minecraft/world/level/levelgen/feature/PillagerOutpostFeature.java.patch
+++ b/patches/minecraft/net/minecraft/world/level/levelgen/feature/PillagerOutpostFeature.java.patch
@@ -1,14 +1,16 @@
 --- a/net/minecraft/world/level/levelgen/feature/PillagerOutpostFeature.java
 +++ b/net/minecraft/world/level/levelgen/feature/PillagerOutpostFeature.java
-@@ -20,8 +_,9 @@
+@@ -20,8 +_,11 @@
        super(p_66562_, 0, true, true);
     }
  
 -   public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142494_() {
 -      return f_66559_;
 +   @Override
-+   public java.util.List<MobSpawnSettings.SpawnerData> getDefaultSpawnList() {
-+      return f_66559_.m_146338_();
++   public java.util.List<MobSpawnSettings.SpawnerData> getDefaultSpawnList(net.minecraft.world.entity.MobCategory category) {
++      if (category == net.minecraft.world.entity.MobCategory.MONSTER)
++         return f_66559_.m_146338_();
++      return java.util.Collections.emptyList();
     }
  
     protected boolean m_142290_(ChunkGenerator p_160197_, BiomeSource p_160198_, long p_160199_, WorldgenRandom p_160200_, ChunkPos p_160201_, Biome p_160202_, ChunkPos p_160203_, JigsawConfiguration p_160204_, LevelHeightAccessor p_160205_) {
diff --git a/patches/minecraft/net/minecraft/world/level/levelgen/feature/StructureFeature.java.patch b/patches/minecraft/net/minecraft/world/level/levelgen/feature/StructureFeature.java.patch
index 8cfbb94544..8806ac6469 100644
--- a/patches/minecraft/net/minecraft/world/level/levelgen/feature/StructureFeature.java.patch
+++ b/patches/minecraft/net/minecraft/world/level/levelgen/feature/StructureFeature.java.patch
@@ -9,17 +9,22 @@
     public static final BiMap<String, StructureFeature<?>> f_67012_ = HashBiMap.create();
     private static final Map<StructureFeature<?>, GenerationStep.Decoration> f_67032_ = Maps.newHashMap();
     private static final Logger f_67033_ = LogManager.getLogger();
-@@ -254,11 +_,16 @@
+@@ -250,15 +_,20 @@
     }
  
-    public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142498_() {
+    public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142494_() {
 -      return MobSpawnSettings.f_151796_;
 +      return getSpawnList(net.minecraft.world.entity.MobCategory.MONSTER);
     }
  
-    public WeightedRandomList<MobSpawnSettings.SpawnerData> m_160477_() {
+    public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142498_() {
 -      return MobSpawnSettings.f_151796_;
 +      return getSpawnList(net.minecraft.world.entity.MobCategory.CREATURE);
+    }
+ 
+    public WeightedRandomList<MobSpawnSettings.SpawnerData> m_160477_() {
+-      return MobSpawnSettings.f_151796_;
++      return getSpawnList(net.minecraft.world.entity.MobCategory.UNDERGROUND_WATER_CREATURE);
 +   }
 +
 +   @Override
diff --git a/patches/minecraft/net/minecraft/world/level/levelgen/feature/SwamplandHutFeature.java.patch b/patches/minecraft/net/minecraft/world/level/levelgen/feature/SwamplandHutFeature.java.patch
index 9f10e9203d..b228d7fedc 100644
--- a/patches/minecraft/net/minecraft/world/level/levelgen/feature/SwamplandHutFeature.java.patch
+++ b/patches/minecraft/net/minecraft/world/level/levelgen/feature/SwamplandHutFeature.java.patch
@@ -1,21 +1,22 @@
 --- a/net/minecraft/world/level/levelgen/feature/SwamplandHutFeature.java
 +++ b/net/minecraft/world/level/levelgen/feature/SwamplandHutFeature.java
-@@ -26,12 +_,14 @@
+@@ -26,12 +_,13 @@
        return SwamplandHutFeature.FeatureStart::new;
     }
  
 -   public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142494_() {
 -      return f_67169_;
-+   @Override
-+   public java.util.List<MobSpawnSettings.SpawnerData> getDefaultSpawnList() {
-+      return f_67169_.m_146338_();
-    }
- 
+-   }
+-
 -   public WeightedRandomList<MobSpawnSettings.SpawnerData> m_142498_() {
 -      return f_67170_;
 +   @Override
-+   public java.util.List<MobSpawnSettings.SpawnerData> getDefaultCreatureSpawnList() {
-+      return f_67170_.m_146338_();
++   public java.util.List<MobSpawnSettings.SpawnerData> getDefaultSpawnList(net.minecraft.world.entity.MobCategory category) {
++      if (category == net.minecraft.world.entity.MobCategory.MONSTER)
++         return f_67169_.m_146338_();
++      else if (category == net.minecraft.world.entity.MobCategory.CREATURE)
++         return f_67170_.m_146338_();
++      return java.util.Collections.emptyList();
     }
  
     public static class FeatureStart extends StructureStart<NoneFeatureConfiguration> {
diff --git a/src/main/java/net/minecraftforge/common/extensions/IForgeStructureFeature.java b/src/main/java/net/minecraftforge/common/extensions/IForgeStructureFeature.java
index c2839bcb62..9ee4d78379 100644
--- a/src/main/java/net/minecraftforge/common/extensions/IForgeStructureFeature.java
+++ b/src/main/java/net/minecraftforge/common/extensions/IForgeStructureFeature.java
@@ -33,10 +33,28 @@ public interface IForgeStructureFeature
         return (StructureFeature<?>) this;
     }
 
+    /**
+     * Gets the default list of spawns for this structure, of the specified category.
+     *
+     * @apiNote Implement this over any of the type specific getSpecial functions in StructureFeature.
+     */
+    @SuppressWarnings("incomplete-switch")
+    default List<MobSpawnSettings.SpawnerData> getDefaultSpawnList(MobCategory category)
+    {
+        if (category == MobCategory.MONSTER)
+            return getDefaultSpawnList();
+        else if (category == MobCategory.CREATURE)
+            return getDefaultCreatureSpawnList();
+        return Collections.emptyList();
+    }
+
     /**
      * Gets the default list of {@link EntityClassification#MONSTER} spawns for this structure.
      *
      * @apiNote Implement this over {@link Structure#getSpawnList()}
+     *
+     * @Deprecated Use {@link IForgeStructureFeature#getDefaultSpawnList(MobCategory)}
+     * TODO: Remove in 1.18
      */
     default List<MobSpawnSettings.SpawnerData> getDefaultSpawnList()
     {
@@ -47,6 +65,9 @@ public interface IForgeStructureFeature
      * Gets the default list of {@link EntityClassification#CREATURE} spawns for this structure.
      *
      * @apiNote Implement this over {@link Structure#getCreatureSpawnList()}
+     *
+     * @Deprecated Use {@link IForgeStructureFeature#getDefaultSpawnList(MobCategory)}
+     * TODO: Remove in 1.18
      */
     default List<MobSpawnSettings.SpawnerData> getDefaultCreatureSpawnList()
     {
diff --git a/src/main/java/net/minecraftforge/common/world/StructureSpawnManager.java b/src/main/java/net/minecraftforge/common/world/StructureSpawnManager.java
index c0d458306a..759f61de6c 100644
--- a/src/main/java/net/minecraftforge/common/world/StructureSpawnManager.java
+++ b/src/main/java/net/minecraftforge/common/world/StructureSpawnManager.java
@@ -111,8 +111,9 @@ public class StructureSpawnManager
      */
     public static WeightedRandomList<MobSpawnSettings.SpawnerData> getSpawnList(StructureFeature<?> structure, MobCategory classification)
     {
-        if (structuresWithSpawns.containsKey(structure))
-            return structuresWithSpawns.get(structure).spawns.getOrDefault(classification, WeightedRandomList.create());
+        StructureSpawnInfo info = structuresWithSpawns.get(structure);
+        if (info != null)
+            return info.spawns.getOrDefault(classification, WeightedRandomList.create());
         return WeightedRandomList.create();
     }
 
diff --git a/src/main/java/net/minecraftforge/event/world/StructureSpawnListGatherEvent.java b/src/main/java/net/minecraftforge/event/world/StructureSpawnListGatherEvent.java
index 28e9e3aaa3..83061c691e 100644
--- a/src/main/java/net/minecraftforge/event/world/StructureSpawnListGatherEvent.java
+++ b/src/main/java/net/minecraftforge/event/world/StructureSpawnListGatherEvent.java
@@ -25,7 +25,9 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import net.minecraft.world.entity.MobCategory;
+import net.minecraft.world.level.SpawnData;
 import net.minecraft.world.level.biome.MobSpawnSettings;
+import net.minecraft.world.level.biome.MobSpawnSettings.SpawnerData;
 import net.minecraft.world.level.levelgen.feature.StructureFeature;
 import net.minecraftforge.eventbus.api.Event;
 
@@ -55,8 +57,12 @@ public class StructureSpawnListGatherEvent extends Event
     {
         this.structure = structure;
         this.insideOnly = this.structure.getDefaultRestrictsSpawnsToInside();
-        addEntitySpawns(MobCategory.MONSTER, this.structure.getDefaultSpawnList());
-        addEntitySpawns(MobCategory.CREATURE, this.structure.getDefaultCreatureSpawnList());
+
+        for (MobCategory cat : MobCategory.values()) {
+            List<SpawnerData> lst = this.structure.getDefaultSpawnList(cat);
+            if (!lst.isEmpty())
+                addEntitySpawns(cat, lst);
+        }
     }
 
     /**