diff --git a/include/mods.h b/include/mods.h
index 3047c8d2..d2a45b0f 100644
--- a/include/mods.h
+++ b/include/mods.h
@@ -97,6 +97,7 @@ void Spawner(void);
 #endif
 
 #define DEBUG_SKIP_BRIEFING 1
+#define DEBUG_BOSS_KILLER 0
 
 /*
 
diff --git a/src/mods/bosskiller.c b/src/mods/bosskiller.c
new file mode 100644
index 00000000..9dfdb993
--- /dev/null
+++ b/src/mods/bosskiller.c
@@ -0,0 +1,236 @@
+#include "global.h"
+
+extern void SectorY_80198F5C(SyShogun* this);
+
+/* Prevent execution before gameplay */
+bool PreventExecution(void) {
+    if ((gGameState != GSTATE_PLAY) || (gPlayState <= PLAY_INIT)) {
+        // Not in gameplay, execution should be prevented to avoid crashes.
+        return true;
+    } else {
+        // In gameplay, fine to proceed.
+        return false;
+    }
+}
+
+void KillBoss(void) {
+    static int bossMercyTimer = 0;
+    static int eventState = 0;
+
+    Actor* actor = &gActors[0];
+    Player* player = &gPlayer[0];
+    Boss* boss = &gBosses[0];
+
+    u16 killButton = L_TRIG;
+    s32 i;
+
+    if (PreventExecution())
+        return;
+
+    RCP_SetupDL(&gMasterDisp, SETUPDL_83);
+    gDPSetPrimColor(gMasterDisp++, 0, 0, 255, 255, 0, 255);
+    Graphics_DisplaySmallNumber(20, 220, bossMercyTimer);
+
+    // gRingPassCount = 7; // for LEVEL_CORNERIA
+    player->mercyTimer = 1000;
+    gLaserStrength[0] = 2;
+
+    if (gControllerPress[0].button & U_JPAD) {
+        // player->state_1C8 = PLAYERSTATE_1C8_START_360;
+        player->baseSpeed += 50;
+    }
+    if (gControllerPress[0].button & D_JPAD) {
+        player->baseSpeed -= 50;
+    }
+
+    if (bossMercyTimer != 0) {
+        bossMercyTimer--;
+    }
+
+    if (gControllerPress[0].button & START_BUTTON)
+        bossMercyTimer = 0;
+
+    if (gControllerPress[0].button & killButton) {
+        switch (gCurrentLevel) {
+            case LEVEL_CORNERIA:
+                if (boss[0].obj.status != OBJ_ACTIVE)
+                    break;
+
+                // Granga
+                if (gLevelMode == LEVELMODE_ALL_RANGE) {
+                    boss[0].dmgType = DMG_BEAM;
+                    boss[0].dmgPart == 0;
+                    boss[0].swork[29] = -1;
+                    gShowBossHealth = false;
+                }
+
+                // Carrier
+                if (gLevelMode == LEVELMODE_ON_RAILS) {
+                    boss[0].dmgType = DMG_BEAM;
+                    boss[1].dmgType = DMG_BEAM;
+                    boss[2].dmgType = DMG_BEAM;
+                    boss[3].dmgType = DMG_BEAM;
+                    boss[0].health = 0;
+                    boss[1].health = 0;
+                    boss[2].health = 0;
+                    boss[3].health = 0;
+                    boss[0].state = 7;
+                    boss[1].state = 1;
+                    boss[2].state = 1;
+                    boss[3].state = 1;
+                    gShowBossHealth = false;
+                }
+                break;
+
+            case LEVEL_METEO:
+                boss[0].dmgType = DMG_BEAM;
+                boss[0].dmgPart = 5;
+                boss[0].dmgPart = 7;
+                boss[0].swork[7] = 0;
+                boss[0].swork[8] = 0;
+                boss[0].health = 0;
+                boss[0].state = 9;
+                break;
+
+            case LEVEL_SECTOR_X:
+                if (boss[0].obj.status != OBJ_ACTIVE) break;
+
+                // Spyborg's fake death
+                if ((eventState == 0) && (bossMercyTimer == 0)) {
+                    boss[0].dmgType = DMG_BEAM;
+                    boss[0].dmgPart = 0;
+                    boss[0].swork[0] = 1;
+                    boss[0].swork[3] = 0;
+                    eventState++;
+                    bossMercyTimer = (60 * 2) / gVIsPerFrame;
+                    break;
+                }
+
+                // Spyborg's actual death
+                if ((eventState == 1) && (bossMercyTimer == 0)) {
+                    boss[0].dmgType = DMG_BEAM;
+                    boss[0].dmgPart = 0;
+                    boss[0].swork[0] = 2;
+                    boss[0].health = 0;
+                    eventState = 0;
+                    bossMercyTimer = (1700 * 2) / gVIsPerFrame;
+                    break;
+                }
+                break;
+
+            case LEVEL_SECTOR_Y:
+                if (bossMercyTimer != 0) {
+                    break;
+                }
+
+                if (boss[1].obj.status == OBJ_ACTIVE) {
+                    bossMercyTimer = (100 * 2) / gVIsPerFrame;
+                    boss[1].dmgType = DMG_BEAM;
+                    boss[1].swork[25] = 1;
+                    boss[1].health = 0;
+                    SectorY_80198F5C(&boss[1]);
+                } else if (boss[2].obj.status == OBJ_ACTIVE) {
+                    bossMercyTimer = (350 * 2) / gVIsPerFrame;
+                    boss[2].dmgType = DMG_BEAM;
+                    boss[1].swork[25] = 1;
+                    boss[2].health = 0;
+                    SectorY_80198F5C(&boss[2]);
+                } else if (boss[0].obj.status == OBJ_ACTIVE) {
+                    bossMercyTimer = (350 * 2) / gVIsPerFrame;
+                    boss[0].dmgType = DMG_BEAM;
+                    boss[1].swork[25] = 1;
+                    boss[0].health = 0;
+                    SectorY_80198F5C(&boss[0]);
+                }
+                break;
+
+            case LEVEL_SECTOR_Z:
+
+                break;
+
+            case LEVEL_AQUAS:
+
+                break;
+
+            case LEVEL_AREA_6:
+
+                break;
+
+            case LEVEL_BOLSE:
+
+                break;
+
+            case LEVEL_FORTUNA:
+                // Call Starwolf
+                if ((eventState == 0) && (player->state_1C8 == PLAYERSTATE_1C8_ACTIVE) && (bossMercyTimer == 0)) {
+                    gAllRangeSpawnEvent = gAllRangeEventTimer + 2;
+                    for (i = 0; i < 6; i++) {
+                        gSavedStarWolfTeamAlive[i] = true;
+                        gStarWolfTeamAlive[i] = true;
+                    }
+                    bossMercyTimer = (500 * 2) / gVIsPerFrame;
+                    eventState++;
+                    break;
+                }
+
+#if 0
+                // Good Ending
+                if ((eventState != 0) && (player->state_1C8 == PLAYERSTATE_1C8_ACTIVE) && (bossMercyTimer == 0)) {
+                    eventState = 0;
+                    gAllRangeEventTimer = (10090 * 2) / gVIsPerFrame;
+                    for (i = 0; i < 4; i++) {
+                        gStarWolfTeamAlive[i] = 0;
+                    }
+                    bossMercyTimer = (1700 * 2) / gVIsPerFrame;
+                    break;
+                }
+#else
+                // Bad Ending
+                if ((eventState != 0) && (player->state_1C8 == PLAYERSTATE_1C8_ACTIVE) && (bossMercyTimer == 0)) {
+                    eventState = 0;
+                    gAllRangeCountdownScale = 1.0f;
+                    gShowAllRangeCountdown = 1;
+                    gAllRangeCountdown[0] = 1;
+                    gAllRangeCountdown[1] = 4;
+                    gAllRangeCountdown[2] = 99;
+                    gAllRangeEventTimer = 9200;
+                    bossMercyTimer = (3000 * 2) / gVIsPerFrame;
+                }
+#endif
+                break;
+
+            case LEVEL_KATINA:
+                // Press the killButton to call the Saucerer
+                if (gAllRangeEventTimer < ((3830 * 2) / gVIsPerFrame)) {
+                    gAllRangeEventTimer = (3830 * 2) / gVIsPerFrame;
+                }
+
+                // Press the killButton to get the Saucerer in position
+                if (boss[1].state == 1) {
+                    boss[1].obj.pos.z = 4499;
+                }
+
+                // Boss in position
+                if (boss[1].state >= 6) {
+#if 0
+                    // Good ending
+                    boss[1].state = 20;
+                    boss[1].timer_050 = 10;
+#else
+                    // bad ending
+                    boss[1].state = 12;
+                    boss[1].timer_050 = 10;
+#endif
+                }
+                break;
+
+            case LEVEL_MACBETH:
+
+                break;
+
+            case LEVEL_SOLAR:
+
+                break;
+        }
+    }
+}
\ No newline at end of file