diff --git a/include/effect.h b/include/effect.h
index 060b6cd0905..782a87ca514 100644
--- a/include/effect.h
+++ b/include/effect.h
@@ -391,7 +391,7 @@ void EffectSsSibuki_SpawnBurst(struct PlayState* play, Vec3f* pos);
 void EffectSsSibuki2_Spawn(struct PlayState* play, Vec3f* pos, Vec3f* velocity, Vec3f* accel, s16 scale);
 void EffectSsGMagma2_Spawn(struct PlayState* play, Vec3f* pos, Color_RGBA8* primColor, Color_RGBA8* envColor,
                            s16 updateRate, s16 drawMode, s16 scale);
-void EffectSsStone1_Spawn(struct PlayState* play, Vec3f* pos, s32 arg2);
+void EffectSsStone1_Spawn(struct PlayState* play, Vec3f* pos, s32 shortenFadeFlash);
 void EffectSsHitMark_Spawn(struct PlayState* play, s32 type, s16 scale, Vec3f* pos);
 void EffectSsHitMark_SpawnFixedScale(struct PlayState* play, s32 type, Vec3f* pos);
 void EffectSsHitMark_SpawnCustomScale(struct PlayState* play, s32 type, s16 scale, Vec3f* pos);
diff --git a/src/code/z_effect_soft_sprite_old_init.c b/src/code/z_effect_soft_sprite_old_init.c
index fea0102140d..b8e4c5033f8 100644
--- a/src/code/z_effect_soft_sprite_old_init.c
+++ b/src/code/z_effect_soft_sprite_old_init.c
@@ -733,11 +733,11 @@ void EffectSsGMagma2_Spawn(PlayState* play, Vec3f* pos, Color_RGBA8* primColor,
 
 // EffectSsStone1 Spawn Functions
 
-void EffectSsStone1_Spawn(PlayState* play, Vec3f* pos, s32 arg2) {
+void EffectSsStone1_Spawn(PlayState* play, Vec3f* pos, s32 shortenFadeFlash) {
     EffectSsStone1InitParams initParams;
 
     initParams.pos = *pos;
-    initParams.unk_C = arg2;
+    initParams.shortenFadeFlash = shortenFadeFlash;
 
     EffectSs_Spawn(play, EFFECT_SS_STONE1, 128, &initParams);
 }
diff --git a/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.c b/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.c
index bdd99e1e319..9aa5607811c 100644
--- a/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.c
+++ b/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.c
@@ -18,7 +18,7 @@
 
 #include "assets/objects/gameplay_keep/gameplay_keep.h"
 
-#define rReg0 regs[0]
+#define rShortenFadeFlash regs[0]
 
 u32 EffectSsStone1_Init(PlayState* play, u32 index, EffectSs* this, void* initParamsx);
 void EffectSsStone1_Draw(PlayState* play, u32 index, EffectSs* this);
@@ -53,7 +53,7 @@ u32 EffectSsStone1_Init(PlayState* play, u32 index, EffectSs* this, void* initPa
     this->pos = pos;
     this->vec = pos;
     this->life = 8;
-    this->rReg0 = initParams->unk_C;
+    this->rShortenFadeFlash = initParams->shortenFadeFlash;
     this->draw = EffectSsStone1_Draw;
     this->update = EffectSsStone1_Update;
 
@@ -85,7 +85,7 @@ void EffectSsStone1_Draw(PlayState* play, u32 index, EffectSs* this) {
 }
 
 void EffectSsStone1_Update(PlayState* play, u32 index, EffectSs* this) {
-    if ((this->life == 6) && (this->rReg0 != 0)) {
+    if ((this->life == 6) && this->rShortenFadeFlash) {
         R_TRANS_FADE_FLASH_ALPHA_STEP = 0;
     }
 }
diff --git a/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.h b/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.h
index c84ab06f9c4..4fd8bb5dc49 100644
--- a/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.h
+++ b/src/overlays/effects/ovl_Effect_Ss_Stone1/z_eff_ss_stone1.h
@@ -6,7 +6,18 @@
 
 typedef struct EffectSsStone1InitParams {
     /* 0x00 */ Vec3f pos;
-    /* 0x00 */ s32 unk_C;
-} EffectSsStone1InitParams; // size = 0x
+
+    /**
+     * If this is non-zero, then on the 2nd frame after being spawned,
+     * the effect will suppress any flash effect from R_TRANS_FADE_FLASH_ALPHA_STEP.
+     * All current users of EffectSsStone1InitParams set this to 0.
+     *
+     * Given that:
+     * - the only use of R_TRANS_FADE_FLASH_ALPHA_STEP is made by arrows, when they're deku nut "arrows"
+     * - arrows are the only thing that spawn this effect
+     * It might be that this parameter was used at some point in development in relation to deku nuts or arrows.
+     */
+    /* 0x0C */ s32 shortenFadeFlash;
+} EffectSsStone1InitParams; // size = 0x10
 
 #endif