diff --git a/zone/mob.cpp b/zone/mob.cpp
index 5e31591e4..b7f32bf94 100644
--- a/zone/mob.cpp
+++ b/zone/mob.cpp
@@ -4924,7 +4924,7 @@ void Mob::ClearSpecialAbilities() {
 	}
 }
 
-void Mob::ProcessSpecialAbilities(const std::string str) {
+void Mob::ProcessSpecialAbilities(const std::string &str) {
 	ClearSpecialAbilities();
 
 	std::vector<std::string> sp = SplitString(str, '^');
diff --git a/zone/mob.h b/zone/mob.h
index 1f1d257f9..07459eab9 100644
--- a/zone/mob.h
+++ b/zone/mob.h
@@ -843,7 +843,7 @@ public:
 	void StopSpecialAbilityTimer(int ability);
 	Timer *GetSpecialAbilityTimer(int ability);
 	void ClearSpecialAbilities();
-	void ProcessSpecialAbilities(const std::string str);
+	void ProcessSpecialAbilities(const std::string &str);
 
 	Shielders_Struct shielder[MAX_SHIELDERS];
 	Trade* trade;