diff --git a/paper-server/patches/sources/net/minecraft/core/Holder.java.patch b/paper-server/patches/sources/net/minecraft/core/Holder.java.patch
new file mode 100644
index 0000000000..634a2b2190
--- /dev/null
+++ b/paper-server/patches/sources/net/minecraft/core/Holder.java.patch
@@ -0,0 +1,11 @@
+--- a/net/minecraft/core/Holder.java
++++ b/net/minecraft/core/Holder.java
+@@ -230,7 +230,7 @@
+         }
+ 
+         void bindTags(Collection<TagKey<T>> tags) {
+-            this.tags = Set.copyOf(tags);
++            this.tags = java.util.Collections.unmodifiableSet(new it.unimi.dsi.fastutil.objects.ReferenceOpenHashSet<>(tags)); // Paper
+         }
+ 
+         @Override
diff --git a/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntityType.java b/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntityType.java
index 6cf8af0c85..d230cbc26f 100644
--- a/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntityType.java
+++ b/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntityType.java
@@ -25,11 +25,11 @@ public class CraftEntityType {
         return bukkit;
     }
 
+    private static final java.util.Map<EntityType, net.minecraft.resources.ResourceKey<net.minecraft.world.entity.EntityType<?>>> KEY_CACHE = java.util.Collections.synchronizedMap(new java.util.EnumMap<>(EntityType.class)); // Paper
     public static net.minecraft.world.entity.EntityType<?> bukkitToMinecraft(EntityType bukkit) {
         Preconditions.checkArgument(bukkit != null);
-
         return CraftRegistry.getMinecraftRegistry(Registries.ENTITY_TYPE)
-                .getOptional(CraftNamespacedKey.toMinecraft(bukkit.getKey())).orElseThrow();
+                .getOptional(KEY_CACHE.computeIfAbsent(bukkit, type -> net.minecraft.resources.ResourceKey.create(Registries.ENTITY_TYPE, CraftNamespacedKey.toMinecraft(type.getKey())))).orElseThrow();
     }
 
     public static Holder<net.minecraft.world.entity.EntityType<?>> bukkitToMinecraftHolder(EntityType bukkit) {