diff --git a/headers/data/overlay10.h b/headers/data/overlay10.h
index 0378597b..067c522e 100644
--- a/headers/data/overlay10.h
+++ b/headers/data/overlay10.h
@@ -26,6 +26,7 @@ extern int16_t WISE_HEALER_PERCENTAGE;
 extern int16_t UNOWN_STONE_DROP_CHANCE;
 extern int16_t SITRUS_BERRY_HP_RESTORATION;
 extern int16_t AMBER_TEAR_RECRUIT_BOOST;
+extern int16_t EARTH_POWER_LOWER_SPECIAL_DEFENSE_CHANCE;
 extern int16_t MUDDY_WATER_LOWER_ACCURACY_CHANCE;
 extern int16_t SILVER_WIND_BOOST_CHANCE;
 extern int16_t POISON_TAIL_POISON_CHANCE;
@@ -52,6 +53,8 @@ extern int16_t ORAN_BERRY_FULL_HP_BOOST;
 extern int16_t LIFE_SEED_HP_BOOST;
 extern int16_t FRIEND_BOW_FAST_FRIEND_BOOST;
 extern int16_t OCTAZOOKA_LOWER_ACCURACY_CHANCE;
+extern int16_t SEED_FLARE_LOWER_SPECIAL_DEFENSE_CHANCE;
+extern int16_t FLASH_CANNON_LOWER_SPECIAL_DEFENSE_CHANCE;
 extern int16_t LUSTER_PURGE_LOWER_SPECIAL_DEFENSE_CHANCE;
 extern int16_t SUPER_LUCK_CRIT_RATE_BOOST;
 extern int16_t CONSTRICT_LOWER_SPEED_CHANCE;
@@ -91,7 +94,9 @@ extern int16_t SITRUS_BERRY_FULL_HP_BOOST;
 extern int16_t SNORE_CRINGE_CHANCE;
 extern int16_t METEOR_MASH_BOOST_ATTACK_CHANCE;
 extern int16_t CRUSH_CLAW_LOWER_DEFENSE_CHANCE;
+extern int16_t ACID_PSYCHIC_LOWER_DEFENSE_CHANCE;
 extern int16_t BURN_DAMAGE_COOLDOWN;
+extern int16_t BUG_BUZZ_LOWER_SPECIAL_DEFENSE_CHANCE;
 extern int16_t SHADOW_BALL_LOWER_SPECIAL_DEFENSE_CHANCE;
 extern int16_t AQUA_RING_HEALING_COUNTDOWN;
 extern int16_t STICK_POWER;
diff --git a/headers/functions/overlay29.h b/headers/functions/overlay29.h
index f9acd410..c3df1d08 100644
--- a/headers/functions/overlay29.h
+++ b/headers/functions/overlay29.h
@@ -629,11 +629,12 @@ void BoostDefensiveStat(struct entity* user, struct entity* target, int stat_idx
 int FlashFireShouldActivate(struct entity* attacker, struct entity* defender);
 void ActivateFlashFire(struct entity* attacker, struct entity* defender);
 void ApplyOffensiveStatMultiplier(struct entity* user, struct entity* target, int stat_idx,
-                                  int multiplier, undefined param_5);
+                                  int multiplier, bool display_message);
 void ApplyDefensiveStatMultiplier(struct entity* user, struct entity* target, int stat_idx,
-                                  int multiplier, undefined param_5);
+                                  int multiplier, bool display_message);
 void BoostHitChanceStat(struct entity* user, struct entity* target, int stat_idx);
-void LowerHitChanceStat(struct entity* user, struct entity* target, int stat_idx, int param_4);
+void LowerHitChanceStat(struct entity* user, struct entity* target, int stat_idx,
+                        bool display_message);
 bool TryInflictCringeStatus(struct entity* user, struct entity* target, bool log_failure,
                             bool check_only);
 bool TryInflictParalysisStatus(struct entity* user, struct entity* target, bool log_failure,
diff --git a/symbols/overlay10.yml b/symbols/overlay10.yml
index 179f3d39..932680d3 100644
--- a/symbols/overlay10.yml
+++ b/symbols/overlay10.yml
@@ -612,6 +612,16 @@ overlay10:
         NA: 0x2
         JP: 0x2
       description: The amount added to the recruit rate when holding an Amber Tear.
+    - name: EARTH_POWER_LOWER_SPECIAL_DEFENSE_CHANCE
+      address:
+        EU: 0x22C4DD8
+        NA: 0x22C4480
+        JP: 0x22C5B68
+      length:
+        EU: 0x2
+        NA: 0x2
+        JP: 0x2
+      description: "The chance of Earth Power lowering special defense, as a percentage (20%)."
     - name: MUDDY_WATER_LOWER_ACCURACY_CHANCE
       address:
         EU: 0x22C4DDC
@@ -872,6 +882,26 @@ overlay10:
         NA: 0x2
         JP: 0x2
       description: "The chance of Octazooka lowering accuracy, as a percentage (60%)."
+    - name: SEED_FLARE_LOWER_SPECIAL_DEFENSE_CHANCE
+      address:
+        EU: 0x22C4E5C
+        NA: 0x22C4504
+        JP: 0x22C5BEC
+      length:
+        EU: 0x2
+        NA: 0x2
+        JP: 0x2
+      description: "The chance of Seed Flare lowering special defense, as a percentage (20%)."
+    - name: FLASH_CANNON_LOWER_SPECIAL_DEFENSE_CHANCE
+      address:
+        EU: 0x22C4E60
+        NA: 0x22C4508
+        JP: 0x22C5BF0
+      length:
+        EU: 0x2
+        NA: 0x2
+        JP: 0x2
+      description: "The chance of Flash Cannon lowering special defense, as a percentage (20%)."
     - name: LUSTER_PURGE_LOWER_SPECIAL_DEFENSE_CHANCE
       address:
         EU: 0x22C4E64
@@ -1260,6 +1290,16 @@ overlay10:
         NA: 0x2
         JP: 0x2
       description: "The chance of Crush Claw lowering defense, as a percentage (50%)."
+    - name: ACID_PSYCHIC_LOWER_DEFENSE_CHANCE
+      address:
+        EU: 0x22C4F64
+        NA: 0x22C460C
+        JP: 0x22C5CF4
+      length:
+        EU: 0x2
+        NA: 0x2
+        JP: 0x2
+      description: "The chance of Acid lowering defense and Psychic lowering special defense, as a percentage (20%)."
     - name: BURN_DAMAGE_COOLDOWN
       address:
         EU: 0x22C4F68
@@ -1270,6 +1310,16 @@ overlay10:
         NA: 0x2
         JP: 0x2
       description: The number of turns between passive burn damage.
+    - name: BUG_BUZZ_LOWER_SPECIAL_DEFENSE_CHANCE
+      address:
+        EU: 0x22C4F6C
+        NA: 0x22C4614
+        JP: 0x22C5CFC
+      length:
+        EU: 0x2
+        NA: 0x2
+        JP: 0x2
+      description: "The chance of Bug Buzz lowering special defense, as a percentage (20%)."
     - name: SHADOW_BALL_LOWER_SPECIAL_DEFENSE_CHANCE
       address:
         EU: 0x22C4F74
diff --git a/symbols/overlay29.yml b/symbols/overlay29.yml
index dbd79913..00f0fbe3 100644
--- a/symbols/overlay29.yml
+++ b/symbols/overlay29.yml
@@ -6227,7 +6227,7 @@ overlay29:
         r1: target entity pointer
         r2: stat index
         r3: multiplier
-        stack[0]: ?
+        stack[0]: whether to display a message indicating the stat multiplier change
     - name: ApplyDefensiveStatMultiplier
       address:
         EU: 0x23149C4
@@ -6242,7 +6242,7 @@ overlay29:
         r1: target entity pointer
         r2: stat index
         r3: multiplier
-        stack[0]: ?
+        stack[0]: whether to display a message indicating the stat multiplier change
     - name: BoostHitChanceStat
       address:
         EU: 0x2314B44