diff --git a/Xplat/src/main/java/vazkii/botania/api/configdata/LooniumStructureConfiguration.java b/Xplat/src/main/java/vazkii/botania/api/configdata/LooniumStructureConfiguration.java
index 6336fbbe6c..8a270a2adb 100644
--- a/Xplat/src/main/java/vazkii/botania/api/configdata/LooniumStructureConfiguration.java
+++ b/Xplat/src/main/java/vazkii/botania/api/configdata/LooniumStructureConfiguration.java
@@ -11,6 +11,7 @@
 import net.minecraft.world.level.levelgen.structure.StructureSpawnOverride;
 
 import vazkii.botania.api.BotaniaAPI;
+import vazkii.botania.common.block.flower.functional.LooniumBlockEntity;
 
 import java.util.List;
 import java.util.Optional;
@@ -46,6 +47,10 @@ public class LooniumStructureConfiguration {
 				if (lsc.spawnedMobs != null && lsc.spawnedMobs.isEmpty()) {
 					return DataResult.error(() -> "Spawned mobs cannot be empty");
 				}
+				if (lsc.manaCost > LooniumBlockEntity.DEFAULT_COST) {
+					return DataResult.error(() -> "Mana costs above %d are currently not supported"
+							.formatted(LooniumBlockEntity.DEFAULT_COST));
+				}
 				return DataResult.success(lsc);
 			});
 	public static final ResourceLocation DEFAULT_CONFIG_ID = new ResourceLocation(BotaniaAPI.MODID, "default");
diff --git a/Xplat/src/main/java/vazkii/botania/common/block/flower/functional/LooniumBlockEntity.java b/Xplat/src/main/java/vazkii/botania/common/block/flower/functional/LooniumBlockEntity.java
index eedff3cc4d..2be8058b53 100644
--- a/Xplat/src/main/java/vazkii/botania/common/block/flower/functional/LooniumBlockEntity.java
+++ b/Xplat/src/main/java/vazkii/botania/common/block/flower/functional/LooniumBlockEntity.java
@@ -274,7 +274,7 @@ private void spawnMob(ServerLevel world, LooniumMobSpawnData pickedMobType,
 		world.levelEvent(LevelEvent.PARTICLES_MOBBLOCK_SPAWN, getBlockPos(), 0);
 		world.gameEvent(mob, GameEvent.ENTITY_PLACE, mob.position());
 
-		addMana(-DEFAULT_COST);
+		addMana(-pickedConfig.manaCost);
 		sync();
 	}