diff --git a/battle/effect_commands.asm b/battle/effect_commands.asm
index 996634376..dc6ca521c 100644
--- a/battle/effect_commands.asm
+++ b/battle/effect_commands.asm
@@ -9557,13 +9557,19 @@ BattleCommand56: ; 37683
 	and a
 	jr z, .asm_3768e
 	ld hl, PlayerScreens
-
 .asm_3768e
-	bit 0, [hl]
+
+; Fails if spikes are already down!
+
+	bit SCREENS_SPIKES, [hl]
 	jr nz, .failed
 
-	set 0, [hl]
+; Nothing else stops it from working.
+
+	set SCREENS_SPIKES, [hl]
+
 	call Function0x37e01
+
 	ld hl, SpikesText
 	jp StdBattleTextBox