diff --git a/zone/aggro.cpp b/zone/aggro.cpp
index a8b23037e..4ddfb759a 100644
--- a/zone/aggro.cpp
+++ b/zone/aggro.cpp
@@ -452,8 +452,26 @@ bool Mob::CheckWillAggro(Mob *mob) {
 		return false;
 	}
 
-	// Don't aggro new clients if we are already engaged unless SpecialAbility::ProximityAggro is set
-	if (IsEngaged() && (!GetSpecialAbility(SpecialAbility::ProximityAggro) || (GetSpecialAbility(SpecialAbility::ProximityAggro) && !CombatRange(mob)))) {
+	// Don't aggro new clients if we are already engaged unless PROX_AGGRO is set
+	// Frustrated mobs (all rooted up with no one to kill)
+	// will engage without PROX_AGGRO ability if someone new is close now.
+
+	const bool is_frustrated = IsRooted() && !CombatRange(target);
+
+	if (
+		!is_frustrated &&
+		IsEngaged() &&
+		(
+			(
+				!GetSpecialAbility(SpecialAbility::ProximityAggro) &&
+				GetBodyType() != BodyType::Undead
+			) ||
+			(
+				GetSpecialAbility(SpecialAbility::ProximityAggro) &&
+				!CombatRange(mob)
+			)
+		)
+	) {
 		LogAggro(
 			"[{}] is in combat, and does not have prox_aggro, or does and is out of combat range with [{}]",
 			GetName(),