diff --git a/src/types/entity/EntityMetadataProperties.php b/src/types/entity/EntityMetadataProperties.php
index 4b3a1c3c..40e837a0 100644
--- a/src/types/entity/EntityMetadataProperties.php
+++ b/src/types/entity/EntityMetadataProperties.php
@@ -160,4 +160,5 @@ private function __construct(){
 	public const PLAYER_DEATH_DIMENSION = 128; //int
 	public const PLAYER_HAS_DIED = 129; //byte
 	public const COLLISION_BOX = 130; //compound
+	public const VISIBLE_MOB_EFFECTS = 131; //long (first 8 visible effects packed, 6 bits for effectId + 1 bit for ambient indicator)
 }