1 files changed, 16 insertions, 1 deletions
diff --git a/src/field_effect_helpers.c b/src/field_effect_helpers.c
index e58fb9b31..95d7ff0b1 100644
--- a/src/field_effect_helpers.c
+++ b/src/field_effect_helpers.c
@@ -37,7 +37,7 @@ static void sub_81278D8(struct Sprite *);
 static void sub_8127FD4(struct MapObject *, struct Sprite *);
 static void sub_812800C(struct MapObject *, struct Sprite *);
 static void sub_81280A0(struct MapObject *, struct Sprite *, struct Sprite *);
-/*static*/ void sub_8128174(struct Sprite *);
+static void sub_8128174(struct Sprite *);
 
 // .rodata
 
@@ -1192,3 +1192,18 @@ u8 sub_8128124(u8 oldSpriteId)
     sprite->data1 = 1;
     return spriteId;
 }
+
+static void sub_8128174(struct Sprite *sprite)
+{
+    struct Sprite *oldSprite;
+
+    oldSprite = &gSprites[sprite->data0];
+    if (((sprite->data2++) & 0x03) == 0)
+    {
+        oldSprite->pos2.y += sprite->data1;
+    }
+    if ((sprite->data2 & 0x0F) == 0)
+    {
+        sprite->data1 = -sprite->data1;
+    }
+}