diff --git a/.bugs b/.bugs
index a8825db0..857c5826 100644
--- a/.bugs
+++ b/.bugs
@@ -106,6 +106,9 @@ patched 264285 server basic
 patched 131562 server basic
 patched 133218 server basic
 patched 158900 server basic
+patched 278019 server basic
+patched 276319 server basic
+patched 277216 server basic
 
 previous 2025 17w47a
 previous 53312 22w17a
diff --git a/src/main/java/dev/isxander/debugify/mixins/basic/mc278019/FlatLevelSourceMixin.java b/src/main/java/dev/isxander/debugify/mixins/basic/mc278019/FlatLevelSourceMixin.java
new file mode 100644
index 00000000..ec4a32f7
--- /dev/null
+++ b/src/main/java/dev/isxander/debugify/mixins/basic/mc278019/FlatLevelSourceMixin.java
@@ -0,0 +1,17 @@
+package dev.isxander.debugify.mixins.basic.mc278019;
+
+import com.llamalad7.mixinextras.injector.ModifyReturnValue;
+import dev.isxander.debugify.fixes.BugFix;
+import dev.isxander.debugify.fixes.FixCategory;
+import net.minecraft.world.level.levelgen.FlatLevelSource;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+
+@BugFix(id = "MC-278019", category = FixCategory.BASIC, env = BugFix.Env.SERVER, modConflicts = "exodus1427", description = "Superflat worlds have their sea level at Y=-63")
+@Mixin(FlatLevelSource.class)
+public class FlatLevelSourceMixin {
+    @ModifyReturnValue(method = "getSeaLevel", at = @At("RETURN"))
+    private int modifySuperflatSeaLevel(int original) {
+        return 63;
+    }
+}
diff --git a/src/main/resources/assets/debugify/lang/en_us.json b/src/main/resources/assets/debugify/lang/en_us.json
index bb907212..6420c2e8 100644
--- a/src/main/resources/assets/debugify/lang/en_us.json
+++ b/src/main/resources/assets/debugify/lang/en_us.json
@@ -89,11 +89,13 @@
   "debugify.fix_explanation.mc-224729": "Always saves ProtoChunks even if the chunk save predicate returns false.",
   "debugify.fix_explanation.mc-226961": "Uses XP Orbs' eye height to determine if it is inside lava.",
   "debugify.fix_effect.mc-226961": "XP Orbs are killed shortly upon touching lava instead of bouncing.",
-  "debugify.fix_explanation.mc-298225": "Fixes skybox getting cut off (i.e. holes/gaps) at low render distances by increasing far plane distance.",
   "debugify.fix_explanation.mc-268617": "Updates the RegEx filter to include all valid path locations. This allows using structure blocks in certain launchers such as Modrinth or any Linux Flatpak launcher.",
   "debugify.fix_explanation.mc-272431": "Fixes the dragon's velocity when traveling to path nodes, making it able to properly traverse to its destination and not circle above it.",
   "debugify.fix_effect.mc-272431": "Prevents zero and one-cycling the dragon as the dragon will no longer slowly perch on the end fountain or above travel nodes.",
+  "debugify.fix_explanation.mc-278019": "Sets the sea level of superflat worlds to Y=63.",
+  "debugify.fix_effect.mc-278019": "This also fixes MC-276319: Aquatic mobs fail to spawn naturally in superflat worlds & MC-277216: Players need to stay below Y=-63 instead of Y=63 to stop Phantoms spawning in superflat worlds",
   "debugify.fix_explanation.mc-297837": "Only use horizontal distance when calculating which waypoint transmitter to use, since large distances use azimuthal distance, which guesses pitch via horizon angle.",
   "debugify.fix_effect.mc-297837": "This allows clients to get exact position of players even when they are far away, but only vertically.",
+  "debugify.fix_explanation.mc-298225": "Fixes skybox getting cut off (i.e. holes/gaps) at low render distances by increasing far plane distance.",
   "debugify.fix_explanation.mc-299115": "The owner's reference is converted to an entity on deflection. This conversion fails if the owner is offline."
 }
diff --git a/src/main/resources/debugify.mixins.json b/src/main/resources/debugify.mixins.json
index d9c6d490..5833af9b 100644
--- a/src/main/resources/debugify.mixins.json
+++ b/src/main/resources/debugify.mixins.json
@@ -20,7 +20,6 @@
     "basic.mc132878.ArmorStandMixin",
     "basic.mc133218.ServerPlayerMixin",
     "basic.mc134110.ChestBlockMixin",
-    "gameplay.mc136249.LivingEntityMixin",
     "basic.mc139041.FishingRodItemMixin",
     "basic.mc147659.CatSpawnerMixin",
     "basic.mc153010.FoxMixin",
@@ -57,6 +56,7 @@
     "basic.mc268617.FileUtilMixin",
     "basic.mc271899.StructureTemplateMixin",
     "basic.mc272431.EnderDragonMixin",
+    "basic.mc278019.FlatLevelSourceMixin",
     "basic.mc297837.WaypointTransmitterMixin",
     "basic.mc298066.LivingEntityMixin",
     "basic.mc30391.LivingEntityMixin",
@@ -69,6 +69,7 @@
     "basic.mc93018.AnimalMixin",
     "basic.mc94054.WallClimberNavigationMixin",
     "errorhandler.CrashReportMixin",
+    "gameplay.mc136249.LivingEntityMixin",
     "gameplay.mc8187.TreeFeatureMixin"
   ]
 }