diff --git a/test/battle/form_change/ultra_burst.c b/test/battle/form_change/ultra_burst.c
new file mode 100644
index 0000000000..1fc5dc83c3
--- /dev/null
+++ b/test/battle/form_change/ultra_burst.c
@@ -0,0 +1,121 @@
+#include "global.h"
+#include "test/battle.h"
+
+SINGLE_BATTLE_TEST("Dusk Mane Necrozma can Ultra Burst holding Ultranecrozium Z")
+{
+    GIVEN {
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, player);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+    } THEN {
+        EXPECT_EQ(player->species, SPECIES_NECROZMA_ULTRA);
+    }
+}
+
+DOUBLE_BATTLE_TEST("Ultra Burst's order is determined by Speed - opponent faster")
+{
+    GIVEN {
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(1); }
+        PLAYER(SPECIES_WOBBUFFET) { Speed(3); }
+        OPPONENT(SPECIES_NECROZMA_DAWN_WINGS) { Item(ITEM_ULTRANECROZIUM_Z); Speed(3); }
+        OPPONENT(SPECIES_WOBBUFFET) { Speed(4); }
+    } WHEN {
+        TURN { MOVE(opponentLeft, MOVE_CELEBRATE, ultraBurst: TRUE); MOVE(playerLeft, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Foe Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, opponentLeft);
+        MESSAGE("Foe Necrozma regained its true power through Ultra Burst!");
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, playerLeft);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+    }
+}
+
+DOUBLE_BATTLE_TEST("Ultra Burst's order is determined by Speed - player faster")
+{
+    GIVEN {
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(5); }
+        PLAYER(SPECIES_WOBBUFFET) { Speed(3); }
+        OPPONENT(SPECIES_NECROZMA_DAWN_WINGS) { Item(ITEM_ULTRANECROZIUM_Z); Speed(2); }
+        OPPONENT(SPECIES_WOBBUFFET) { Speed(4); }
+    } WHEN {
+        TURN { MOVE(opponentLeft, MOVE_CELEBRATE, ultraBurst: TRUE); MOVE(playerLeft, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, playerLeft);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+        MESSAGE("Bright light is about to burst out of Foe Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, opponentLeft);
+        MESSAGE("Foe Necrozma regained its true power through Ultra Burst!");
+    }
+}
+
+SINGLE_BATTLE_TEST("Ultra Burst affects turn order")
+{
+    GIVEN {
+        ASSUME(B_MEGA_EVO_TURN_ORDER);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(105); }
+        OPPONENT(SPECIES_WOBBUFFET) { Speed(106); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Necrozma used Celebrate!");
+        MESSAGE("Foe Wobbuffet used Celebrate!");
+    } THEN {
+        ASSUME(player->speed == 205);
+    }
+}
+
+DOUBLE_BATTLE_TEST("Ultra Burst happens after switching, but before Focus Punch-like Moves")
+{
+    GIVEN {
+        ASSUME(gBattleMoves[MOVE_FOCUS_PUNCH].effect == EFFECT_FOCUS_PUNCH);
+        PLAYER(SPECIES_WOBBUFFET);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); }
+        OPPONENT(SPECIES_WYNAUT);
+        OPPONENT(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { SWITCH(opponentRight, 2); MOVE(playerRight, MOVE_FOCUS_PUNCH, ultraBurst: TRUE, target: opponentLeft); MOVE(playerLeft, MOVE_FOCUS_PUNCH, target: opponentLeft); }
+        TURN {}
+    } SCENE {
+        MESSAGE("2 withdrew Wobbuffet!");
+        MESSAGE("2 sent out Wobbuffet!");
+
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, playerRight);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_FOCUS_PUNCH_SETUP, playerRight);
+        MESSAGE("Necrozma is tightening its focus!");
+
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_FOCUS_PUNCH_SETUP, playerLeft);
+        MESSAGE("Wobbuffet is tightening its focus!");
+    }
+}
+
+SINGLE_BATTLE_TEST("Ultra Burst and Mega Evolution can happen on the same turn")
+{
+    GIVEN {
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(3); }
+        OPPONENT(SPECIES_GARDEVOIR) { Item(ITEM_GARDEVOIRITE); Speed(2); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE, ultraBurst: TRUE); MOVE(opponent, MOVE_CELEBRATE, megaEvolve: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, player);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+
+        MESSAGE("Foe Gardevoir's Gardevoirite is reacting to 's Mega Ring!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_MEGA_EVOLUTION, opponent);
+        MESSAGE("Foe Gardevoir has Mega Evolved into Mega Gardevoir!");
+    } THEN {
+        EXPECT_EQ(player->species, SPECIES_NECROZMA_ULTRA);
+        EXPECT_EQ(opponent->species, SPECIES_GARDEVOIR_MEGA);
+    }
+}