From 24c595bfec5f8467916a49a138c1ce2cf4689c99 Mon Sep 17 00:00:00 2001
From: FosterProgramming <jamiefosterandco@gmail.com>
Date: Mon, 20 Oct 2025 13:38:01 +0200
Subject: [PATCH] Fix psychic terrain affecting semi-invulnerable mons (#7986)

---
 src/battle_util.c                         |  3 +--
 test/battle/move_effect/psychic_terrain.c | 32 +++++++++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/battle_util.c b/src/battle_util.c
index 617bb8b2e5..b0206f98bd 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -2403,8 +2403,7 @@ static enum MoveCanceller CancellerProtean(void)
 
 static enum MoveCanceller CancellerPsychicTerrain(void)
 {
-    if (gFieldStatuses & STATUS_FIELD_PSYCHIC_TERRAIN
-        && IsBattlerGrounded(gBattlerTarget)
+    if (IsBattlerTerrainAffected(gBattlerTarget, STATUS_FIELD_PSYCHIC_TERRAIN)
         && GetChosenMovePriority(gBattlerAttacker, GetBattlerAbility(gBattlerAttacker)) > 0
         && GetMoveTarget(gCurrentMove) != MOVE_TARGET_ALL_BATTLERS
         && GetMoveTarget(gCurrentMove) != MOVE_TARGET_OPPONENTS_FIELD
diff --git a/test/battle/move_effect/psychic_terrain.c b/test/battle/move_effect/psychic_terrain.c
index b85653a0be..2c5089c704 100644
--- a/test/battle/move_effect/psychic_terrain.c
+++ b/test/battle/move_effect/psychic_terrain.c
@@ -114,6 +114,38 @@ SINGLE_BATTLE_TEST("Psychic Terrain doesn't block priority field moves")
     }
 }
 
+SINGLE_BATTLE_TEST("Psychic Terrain doesn't block priority moves against semi-invulnerable targets")
+{
+    u32 move = 0, shouldWork = 0;
+    PARAMETRIZE { move = MOVE_SOLAR_BEAM; shouldWork = FALSE;}
+    PARAMETRIZE { move = MOVE_FLY; shouldWork = TRUE;}
+    GIVEN {
+        PLAYER(SPECIES_SHROODLE) { Ability(ABILITY_PRANKSTER); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_PSYCHIC_TERRAIN); MOVE(opponent,move);}
+        TURN { MOVE(player, MOVE_TOXIC); SKIP_TURN(opponent);}
+    } SCENE {
+        if (shouldWork)
+        {
+            ANIMATION(ANIM_TYPE_MOVE, MOVE_TOXIC, player);
+            ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_PSN, opponent);
+        }
+        else
+        {
+            NONE_OF {
+                ANIMATION(ANIM_TYPE_MOVE, MOVE_TOXIC, player);
+                ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_PSN, opponent);
+            }
+        }
+    } THEN {
+        if (shouldWork)
+            EXPECT(opponent->status1 & STATUS1_TOXIC_POISON);
+        else
+            EXPECT(!(opponent->status1 & STATUS1_TOXIC_POISON));
+    }
+}
+
 SINGLE_BATTLE_TEST("Psychic Terrain lasts for 5 turns")
 {
     GIVEN {