diff --git a/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/DataWatcherKey.java b/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/DataWatcherKey.java
index 76c3fc13..5dcc9030 100644
--- a/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/DataWatcherKey.java
+++ b/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/DataWatcherKey.java
@@ -16,6 +16,7 @@ import java.util.Optional;
 class DataWatcherKey<T> {
 
     private static final DataWatcherSerializer<Byte> BYTE_SERIALIZER = DataWatcherRegistry.a;
+    private static final DataWatcherSerializer<Integer> INT_SERIALIZER = DataWatcherRegistry.b;
     private static final DataWatcherSerializer<Boolean> BOOLEAN_SERIALIZER = DataWatcherRegistry.i;
     private static final DataWatcherSerializer<ItemStack> ITEM_STACK_SERIALIZER = DataWatcherRegistry.g;
     private static final DataWatcherSerializer<Optional<IChatBaseComponent>> OPTIONAL_CHAT_COMPONENT_SERIALIZER = DataWatcherRegistry.f;
@@ -25,6 +26,7 @@ class DataWatcherKey<T> {
     static DataWatcherKey<Boolean> CUSTOM_NAME_VISIBILITY = new DataWatcherKey<>(3, BOOLEAN_SERIALIZER);
     static DataWatcherKey<ItemStack> ITEM_STACK = new DataWatcherKey<>(8, ITEM_STACK_SERIALIZER);
     static DataWatcherKey<Byte> ARMOR_STAND_STATUS = new DataWatcherKey<>(15, BYTE_SERIALIZER);
+    static DataWatcherKey<Integer> SLIME_SIZE = new DataWatcherKey<>(16, INT_SERIALIZER);
 
     private final int index;
     private final DataWatcherSerializer<T> serializer;
diff --git a/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/EntityMetadataNMSPacket.java b/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/EntityMetadataNMSPacket.java
index 3102626d..765f2b23 100644
--- a/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/EntityMetadataNMSPacket.java
+++ b/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/EntityMetadataNMSPacket.java
@@ -75,6 +75,11 @@ class EntityMetadataNMSPacket extends VersionNMSPacket {
             return this;
         }
 
+        Builder setSmallSlime() {
+            packetByteBuffer.writeDataWatcherEntry(DataWatcherKey.SLIME_SIZE, 1);
+            return this;
+        }
+
         EntityMetadataNMSPacket build() {
             packetByteBuffer.writeDataWatcherEntriesEnd();
             return new EntityMetadataNMSPacket(packetByteBuffer);
diff --git a/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/VersionNMSPacketList.java b/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/VersionNMSPacketList.java
index cb281882..061eb98e 100644
--- a/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/VersionNMSPacketList.java
+++ b/nms/v1_17_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_17_R1/VersionNMSPacketList.java
@@ -87,6 +87,7 @@ class VersionNMSPacketList extends AbstractNMSPacketList {
         add(new EntityLivingSpawnNMSPacket(entityID, EntityTypeID.SLIME, locationX, locationY, locationZ));
         add(EntityMetadataNMSPacket.builder(entityID)
                 .setInvisible()
+                .setSmallSlime() // Required for a correct client-side collision box
                 .build()
         );
     }