diff --git a/src/game/SpellEffects.cpp b/src/game/SpellEffects.cpp
index 870e572c0..6b4e689b6 100644
--- a/src/game/SpellEffects.cpp
+++ b/src/game/SpellEffects.cpp
@@ -1030,6 +1030,21 @@ void Spell::EffectDummy(SpellEffectIndex eff_idx)
 
                     return;
                 }
+                case 21147:                                 // Arcane Vacuum
+                {
+                    if (!unitTarget)
+                        return;
+
+                    // Spell used by Azuregos to teleport all the players to him
+                    // This also resets the target threat
+                    if (m_caster->getThreatManager().getThreat(unitTarget))
+                        m_caster->getThreatManager().modifyThreatPercent(unitTarget, -100);
+
+                    // cast summon player
+                    m_caster->CastSpell(unitTarget, 21150, true);
+
+                    return;
+                }
                 case 23019:                                 // Crystal Prison Dummy DND
                 {
                     if (!unitTarget || !unitTarget->isAlive() || unitTarget->GetTypeId() != TYPEID_UNIT || ((Creature*)unitTarget)->IsPet())
diff --git a/src/game/ThreatManager.h b/src/game/ThreatManager.h
index 6159435b5..11dd4e070 100644
--- a/src/game/ThreatManager.h
+++ b/src/game/ThreatManager.h
@@ -56,7 +56,11 @@ class MANGOS_DLL_SPEC HostileReference : public Reference<Unit, ThreatManager>
 
         void setThreat(float pThreat) { addThreat(pThreat - getThreat()); }
 
-        void addThreatPercent(int32 pPercent) { float tmpThreat = iThreat; tmpThreat = tmpThreat * (pPercent+100) / 100; addThreat(tmpThreat-iThreat); }
+        void addThreatPercent(int32 pPercent)
+        {
+            // for special -100 case avoid rounding
+            addThreat(pPercent == -100 ? -iThreat : iThreat * pPercent / 100.0f);
+        }
 
         float getThreat() const { return iThreat; }
 
diff --git a/src/shared/revision_nr.h b/src/shared/revision_nr.h
index 2477872f0..4873598e9 100644
--- a/src/shared/revision_nr.h
+++ b/src/shared/revision_nr.h
@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "11470"
+ #define REVISION_NR "11471"
 #endif // __REVISION_NR_H__