Parting Shot

Effect plus animation (looks like Snarl)

data/battle_anim_scripts.s

@@ -2378,6 +2378,21 @@ Move_DISARMING_VOICE:
 	end
 	
 Move_PARTING_SHOT:
+	loadspritegfx ANIM_TAG_NOISE_LINE
+	fadetobg BG_DARK
+	waitbgfadein
+	delay 0
+	createvisualtask sub_8158E9C, 2, 0, 255
+	call RoarEffect
+	delay 10
+	createvisualtask AnimTask_ShakeMon2, 2, ANIM_TARGET, 1, 0, 9, 1
+	createvisualtask AnimTask_ShakeMon2, 2, ANIM_DEF_PARTNER, 1, 0, 9, 1
+	waitforvisualfinish
+	createvisualtask sub_8159078, 5
+	waitforvisualfinish
+	delay 1
+	restorebg
+	waitbgfadein
 	end
 	
 Move_TOPSY_TURVY:

data/battle_scripts_1.s

@@ -342,6 +342,47 @@ gBattleScriptsForMoveEffects:: @ 82D86A8
 	.4byte BattleScript_EffectPowder
 	.4byte BattleScript_EffectSpAtkUpHit
 	.4byte BattleScript_EffectBelch
+	.4byte BattleScript_EffectPartingShot
+	
+BattleScript_EffectPartingShot::
+	attackcanceler
+	attackstring
+	ppreduce
+	jumpifstat BS_TARGET, CMP_GREATER_THAN, STAT_ATK, 0x0, BattleScript_EffectPartingShotTryAtk
+	jumpifstat BS_TARGET, CMP_EQUAL, STAT_SPATK, 0x0, BattleScript_CantLowerMultipleStats
+BattleScript_EffectPartingShotTryAtk:
+	accuracycheck BattleScript_PrintMoveMissed, ACC_CURR_MOVE	
+	attackanimation
+	waitanimation
+	setbyte sSTAT_ANIM_PLAYED, FALSE
+	playstatchangeanimation BS_TARGET, BIT_ATK | BIT_SPATK, ATK48_STAT_NEGATIVE | ATK48_ONLY_MULTIPLE
+	playstatchangeanimation BS_TARGET, BIT_ATK, ATK48_STAT_NEGATIVE
+	setstatchanger STAT_ATK, 1, TRUE
+	statbuffchange 0x1, BattleScript_EffectPartingShotTrySpAtk
+	printfromtable gStatDownStringIds
+	waitmessage 0x40
+BattleScript_EffectPartingShotTrySpAtk:
+	playstatchangeanimation BS_TARGET, BIT_SPATK, ATK48_STAT_NEGATIVE
+	setstatchanger STAT_SPATK, 1, TRUE
+	statbuffchange 0x1, BattleScript_MoveEnd
+	printfromtable gStatDownStringIds
+	waitmessage 0x40
+	jumpifcantswitch ATK4F_DONT_CHECK_STATUSES | BS_ATTACKER, BattleScript_MoveEnd
+	openpartyscreen BS_ATTACKER, BattleScript_ButItFailed
+	printstring STRINGID_PKMNWENTBACK
+	switchoutabilities BS_ATTACKER
+	waitstate
+	switchhandleorder BS_ATTACKER, 0x2
+	returnatktoball
+	waitstate
+	getswitchedmondata BS_ATTACKER
+	switchindataupdate BS_ATTACKER
+	hpthresholds BS_ATTACKER
+	printstring STRINGID_SWITCHINMON
+	switchinanim BS_ATTACKER, TRUE
+	waitstate
+	switchineffects BS_ATTACKER
+	goto BattleScript_MoveEnd
 	
 BattleScript_EffectSpAtkUpHit:
 	setmoveeffect MOVE_EFFECT_SP_ATK_PLUS_1 | MOVE_EFFECT_AFFECTS_USER

include/constants/battle_move_effects.h

@@ -330,5 +330,6 @@
 #define EFFECT_POWDER 324
 #define EFFECT_SP_ATTACK_UP_HIT 325
 #define EFFECT_BELCH 326
+#define EFFECT_PARTING_SHOT 327
 
 #endif  // GUARD_CONSTANTS_BATTLE_MOVE_EFFECTS_H

src/data/battle_moves.h

@@ -8069,7 +8069,7 @@ const struct BattleMove gBattleMoves[MOVES_COUNT] =
 
     [MOVE_PARTING_SHOT] =
     {
-        .effect = EFFECT_PLACEHOLDER, // Needs a custom move effect
+        .effect = EFFECT_PARTING_SHOT,
         .power = 0,
         .type = TYPE_DARK,
         .accuracy = 100,