diff --git a/Spigot-Server-Patches/0508-Fix-CraftServer.unloadWorld-Leak.patch b/Spigot-Server-Patches/0508-Fix-CraftServer.unloadWorld-Leak.patch
new file mode 100644
index 000000000..eda0a2f3a
--- /dev/null
+++ b/Spigot-Server-Patches/0508-Fix-CraftServer.unloadWorld-Leak.patch
@@ -0,0 +1,123 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <aikar@aikar.co>
+Date: Fri, 8 May 2020 20:30:58 -0400
+Subject: [PATCH] Fix CraftServer.unloadWorld Leak
+
+The dimension manager was still registered which leaked the entire World
+
+diff --git a/src/main/java/net/minecraft/server/DimensionManager.java b/src/main/java/net/minecraft/server/DimensionManager.java
+index 5724fe6e57d3671b4978aecaf217ac4c2e0d7f82..3af9709a8717b1d9c445c3b04163027177a81711 100644
+--- a/src/main/java/net/minecraft/server/DimensionManager.java
++++ b/src/main/java/net/minecraft/server/DimensionManager.java
+@@ -20,6 +20,14 @@ public class DimensionManager implements MinecraftSerializable {
+     private final boolean hasSkyLight;
+     private final GenLayerZoomer genLayerZoomer;
+ 
++    // Paper start
++    public static void unregister(String s, DimensionManager dimensionmanager) {
++        MinecraftServer.getServer().execute(() -> {
++            RegistryMaterials<DimensionManager> registry = (RegistryMaterials<DimensionManager>) IRegistry.DIMENSION_TYPE;
++            registry.deleteValue(new MinecraftKey(s), dimensionmanager);
++        });
++    }
++    // Paper end
+     public static DimensionManager register(String s, DimensionManager dimensionmanager) {
+         return (DimensionManager) IRegistry.a(IRegistry.DIMENSION_TYPE, dimensionmanager.id, s, dimensionmanager);
+     }
+diff --git a/src/main/java/net/minecraft/server/RegistryID.java b/src/main/java/net/minecraft/server/RegistryID.java
+index e8a48b9a4c999281869dfb85577c2b44d6e30eb7..5335e7acc85f0fe9699e5ed59e5aaae5f381347d 100644
+--- a/src/main/java/net/minecraft/server/RegistryID.java
++++ b/src/main/java/net/minecraft/server/RegistryID.java
+@@ -9,12 +9,26 @@ import javax.annotation.Nullable;
+ public class RegistryID<K> implements Registry<K> {
+ 
+     private static final Object a = null;
+-    private K[] b;
++    private K[] b; // Paper - diff below
+     private int[] c;
+-    private K[] d;
++    private K[] d; // Paper - diff below
+     private int e;
+     private int f;
+     private java.util.BitSet usedIds; // Paper
++    // Paper start
++    public void removeValue(K value) {
++        removeValue(value, this.b);
++        removeValue(value, this.d);
++        rehash(this.b.length);
++    }
++    public void removeValue(K value, K[] arr) {
++        for (int i = 0; i < arr.length; i++) {
++            K k = arr[i];
++            if (k == value) {
++                arr[i] = null;
++            }
++        }
++    }
+ 
+     public RegistryID(int i) {
+         i = (int) ((float) i / 0.8F);
+@@ -58,6 +72,7 @@ public class RegistryID<K> implements Registry<K> {
+         return this.e;
+     }
+ 
++    private void rehash(int i) { d(i); } // Paper - OBFHELPER
+     private void d(int i) {
+         K[] ak = this.b;
+         int[] aint = this.c;
+diff --git a/src/main/java/net/minecraft/server/RegistryMaterials.java b/src/main/java/net/minecraft/server/RegistryMaterials.java
+index 8477febca23b575da21023b4d7c18bb679cf3b30..dcdd8d38dee89ae7ac404a431e51a61c50b6d45c 100644
+--- a/src/main/java/net/minecraft/server/RegistryMaterials.java
++++ b/src/main/java/net/minecraft/server/RegistryMaterials.java
+@@ -22,18 +22,23 @@ public class RegistryMaterials<T> extends IRegistryWritable<T> {
+     private int V;
+ 
+     public RegistryMaterials() {}
++    public T deleteValue(MinecraftKey minecraftkey, T value) {
++        this.b.removeValue(value); // Diff 1
++        this.d = null; // Diff 2
++        return this.c.remove(minecraftkey); // Diff 3
++    }
+ 
+     @Override
+     public <V extends T> V a(int i, MinecraftKey minecraftkey, V v0) {
+-        this.b.a(v0, i);
++        this.b.a(v0, i); // Paper - diff above 1
+         Validate.notNull(minecraftkey);
+         Validate.notNull(v0);
+-        this.d = null;
++        this.d = null; // Diff 2
+         if (this.c.containsKey(minecraftkey)) {
+             RegistryMaterials.LOGGER.debug("Adding duplicate key '{}' to registry", minecraftkey);
+         }
+ 
+-        this.c.put(minecraftkey, v0);
++        this.c.put(minecraftkey, v0); // Paper - diff3
+         if (this.V <= i) {
+             this.V = i + 1;
+         }
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+index b89f99a66fe2ab9ad4c956c38c9e4b1d79716c9c..5a40661c1cecde80760f4f87027f7ca8cde6817e 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
++++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+@@ -60,6 +60,7 @@ import net.minecraft.server.EntityPlayer;
+ import net.minecraft.server.EnumDifficulty;
+ import net.minecraft.server.EnumGamemode;
+ import net.minecraft.server.IRecipe;
++import net.minecraft.server.IRegistry;
+ import net.minecraft.server.Item;
+ import net.minecraft.server.ItemWorldMap;
+ import net.minecraft.server.Items;
+@@ -1099,7 +1100,11 @@ public final class CraftServer implements Server {
+         }
+ 
+         worlds.remove(world.getName().toLowerCase(java.util.Locale.ENGLISH));
+-        console.worldServer.remove(handle.getWorldProvider().getDimensionManager());
++        // Paper start
++        DimensionManager dimensionManager = handle.getWorldProvider().getDimensionManager();
++        DimensionManager.unregister(world.getName(), dimensionManager);
++        console.worldServer.remove(dimensionManager);
++        // Paper end
+         return true;
+     }
+