diff --git a/src/main/java/org/spongepowered/common/data/holder/SpongeMutableDataHolder.java b/src/main/java/org/spongepowered/common/data/holder/SpongeMutableDataHolder.java
index c4fa8a33472..3423e86d85a 100644
--- a/src/main/java/org/spongepowered/common/data/holder/SpongeMutableDataHolder.java
+++ b/src/main/java/org/spongepowered/common/data/holder/SpongeMutableDataHolder.java
@@ -37,6 +37,7 @@
 import org.spongepowered.api.data.value.Value;
 import org.spongepowered.api.data.value.ValueContainer;
 import org.spongepowered.common.data.key.SpongeKey;
+import org.spongepowered.common.data.provider.GenericMutableDataProvider;
 import org.spongepowered.common.util.DataUtil;
 
 import java.util.Collection;
@@ -89,6 +90,9 @@ default <E> DataTransactionResult offerSingle(Key<? extends CollectionValue<E, ?
         final SpongeKey<? extends CollectionValue<E, Collection<E>>, Collection<E>> key0 =
                 (SpongeKey<? extends CollectionValue<E, Collection<E>>, Collection<E>>) key;
         return this.impl$applyTransaction(key0, (p, m) -> {
+            if (p instanceof GenericMutableDataProvider) {
+                return ((GenericMutableDataProvider)p).offerSingle(m, element);
+            }
                     final Collection<E> collection = p.get(m)
                             .map(DataUtil::ensureMutable)
                             .orElseGet(key0.getDefaultValueSupplier());
diff --git a/src/main/java/org/spongepowered/common/data/provider/DataProviderRegistrator.java b/src/main/java/org/spongepowered/common/data/provider/DataProviderRegistrator.java
index c1d471545fa..2ca674f5454 100644
--- a/src/main/java/org/spongepowered/common/data/provider/DataProviderRegistrator.java
+++ b/src/main/java/org/spongepowered/common/data/provider/DataProviderRegistrator.java
@@ -41,6 +41,7 @@
 import org.spongepowered.api.data.persistence.DataContentUpdater;
 import org.spongepowered.api.data.persistence.DataStore;
 import org.spongepowered.api.data.persistence.DataView;
+import org.spongepowered.api.data.value.CollectionValue;
 import org.spongepowered.api.data.value.Value;
 import org.spongepowered.api.registry.DefaultedRegistryReference;
 import org.spongepowered.api.util.OptBool;
@@ -54,6 +55,7 @@
 
 import java.lang.reflect.Type;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Optional;
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
@@ -205,6 +207,13 @@ protected <K, V extends Value<K>> MutableRegistrator<T> register(final MutableRe
             this.registrationBuilder.dataKey(provider.key()).provider(provider);
             return this;
         }
+
+        @SuppressWarnings({"unchecked", "UnstableApiUsage"})
+        protected <K, V extends Value<K>, L> MutableRegistrator<T> register(final MutableCollectionRegistration<T, K, L> registration) {
+            final DataProvider<?, ?> provider = registration.build(this.target);
+            this.registrationBuilder.dataKey(provider.key()).provider(provider);
+            return this;
+        }
     }
 
     public static final class ImmutableRegistrator<T> extends DataProviderRegistrator {
@@ -400,6 +409,15 @@ protected boolean supports(final H dataHolder) {
                     }
                     return super.supports(dataHolder);
                 }
+
+                @Override
+                public <TE> DataTransactionResult offerSingle(final DataHolder.Mutable dataHolder, final TE element) {
+                    if (registration instanceof MutableCollectionRegistration<?, ?, ?> haha && haha.single != null) {
+                        ((BiConsumer<H, TE>)haha.single).accept((H) dataHolder, element);
+                        return DataTransactionResult.successNoData();
+                    }
+                    return DataTransactionResult.failNoData();
+                }
             };
 
 
@@ -426,6 +444,12 @@ public <NE> MutableRegistration<H, NE> create(final Key<? extends Value<NE>> key
             return registration;
         }
 
+        public <NE extends CollectionValue<?, V>, V extends Collection<VE>, VE> MutableCollectionRegistration<H, V, VE> createCollection(final Key<? extends NE> key) {
+            final MutableCollectionRegistration<H, V, VE> registration = new MutableCollectionRegistration<H, V, VE>(this.registrator, key);
+            this.registrator.register(registration);
+            return registration;
+        }
+
         /**
          * Creates a new {@link MutableRegistrator}
          * @return The registrator
@@ -443,6 +467,33 @@ public <NT> ImmutableRegistrator<NT> asImmutable(final Class<NT> target) {
         }
     }
 
+    public static final class MutableCollectionRegistration<H, E, V> extends MutableRegistrationBase<H, E, MutableCollectionRegistration<H, E, V>> {
+
+        private final MutableRegistrator<H> registrator;
+
+        @Nullable BiConsumer<H, V> single;
+
+        private MutableCollectionRegistration(final MutableRegistrator<H> registrator, final Key<? extends Value<E>> key) {
+            super(key);
+            this.registrator = registrator;
+        }
+
+        public <NE> MutableRegistration<H, NE> create(final DefaultedRegistryReference<? extends Key<? extends Value<NE>>> suppliedKey) {
+            return this.create(suppliedKey.get());
+        }
+
+        public <NE> MutableRegistration<H, NE> create(final Key<? extends Value<NE>> key) {
+            final MutableRegistration<H, NE> registration = new MutableRegistration<>(this.registrator, key);
+            this.registrator.register(registration);
+            return registration;
+        }
+
+        public MutableCollectionRegistration<H, E, V> single(BiConsumer<H, V> single) {
+            this.single = single;
+            return this;
+        }
+    }
+
     @SuppressWarnings("unchecked")
     private static class ImmutableRegistrationBase<H, E, R extends ImmutableRegistrationBase<H, E, R>> {
         private final Key<? extends Value<E>> key;
diff --git a/src/main/java/org/spongepowered/common/data/provider/GenericMutableDataProviderBase.java b/src/main/java/org/spongepowered/common/data/provider/GenericMutableDataProviderBase.java
index 28108fdb833..b2426f2f2ea 100644
--- a/src/main/java/org/spongepowered/common/data/provider/GenericMutableDataProviderBase.java
+++ b/src/main/java/org/spongepowered/common/data/provider/GenericMutableDataProviderBase.java
@@ -235,4 +235,8 @@ public final DataTransactionResult remove(final DataHolder.Mutable dataHolder) {
         }
         return this.deleteAndGetResult((H) dataHolder);
     }
+
+    public <TE> DataTransactionResult offerSingle(final DataHolder.Mutable dataHolder, final TE element) {
+        return DataTransactionResult.failNoData();
+    }
 }
diff --git a/src/main/java/org/spongepowered/common/data/provider/entity/LivingData.java b/src/main/java/org/spongepowered/common/data/provider/entity/LivingData.java
index da6619568b5..34bcc151b35 100644
--- a/src/main/java/org/spongepowered/common/data/provider/entity/LivingData.java
+++ b/src/main/java/org/spongepowered/common/data/provider/entity/LivingData.java
@@ -156,7 +156,7 @@ public static void register(final DataProviderRegistrator registrator) {
                     .create(Keys.MAX_HEALTH)
                         .get(h -> (double) h.getMaxHealth())
                         .set((h, v) -> h.getAttribute(Attributes.MAX_HEALTH).setBaseValue(v))
-                    .create(Keys.POTION_EFFECTS)
+                    .createCollection(Keys.POTION_EFFECTS)
                         .get(h -> {
                             final Collection<MobEffectInstance> effects = h.getActiveEffects();
                             return PotionEffectUtil.copyAsPotionEffects(effects);
@@ -167,6 +167,9 @@ public static void register(final DataProviderRegistrator registrator) {
                                 h.addEffect(PotionEffectUtil.copyAsEffectInstance(effect));
                             }
                         })
+                        .single((h, v) -> {
+                            h.addEffect(PotionEffectUtil.copyAsEffectInstance(v));
+                        })
                     .create(Keys.SCALE)
                         .get(h -> (double) h.getScale())
                     .create(Keys.STUCK_ARROWS)