diff --git a/test/battle/inverse_battle.c b/test/battle/inverse_battle.c
new file mode 100644
index 0000000000..afa1ff23b0
--- /dev/null
+++ b/test/battle/inverse_battle.c
@@ -0,0 +1,124 @@
+#include "global.h"
+#include "test/battle.h"
+
+static bool32 IsSpeciesMonotypeOf(u32 species, enum Type type)
+{
+    return GetSpeciesType(species, 0) == type && GetSpeciesType(species, 1) == type;
+}
+
+ASSUMPTIONS
+{
+    // Pokemon Types
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_EEVEE,    TYPE_NORMAL));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_MACHAMP,  TYPE_FIGHTING));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_TORNADUS, TYPE_FLYING));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_ARBOK,    TYPE_POISON));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_DUGTRIO,  TYPE_GROUND));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_SUDOWOODO,TYPE_ROCK));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_PINSIR,   TYPE_BUG));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_DUSKULL,  TYPE_GHOST));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_REGISTEEL,TYPE_STEEL));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_FLAREON,  TYPE_FIRE));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_VAPOREON, TYPE_WATER));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_LEAFEON,  TYPE_GRASS));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_JOLTEON,  TYPE_ELECTRIC));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_ESPEON,   TYPE_PSYCHIC));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_GLACEON,  TYPE_ICE));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_DRUDDIGON,TYPE_DRAGON));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_UMBREON,  TYPE_DARK));
+    ASSUME(IsSpeciesMonotypeOf(SPECIES_SYLVEON,  TYPE_FAIRY));
+
+    // Move types
+    ASSUME(GetMoveType(MOVE_TACKLE)        == TYPE_NORMAL);
+    ASSUME(GetMoveType(MOVE_KARATE_CHOP)   == TYPE_FIGHTING);
+    ASSUME(GetMoveType(MOVE_GUST)          == TYPE_FLYING);
+    ASSUME(GetMoveType(MOVE_POISON_STING)  == TYPE_POISON);
+    ASSUME(GetMoveType(MOVE_MUD_SLAP)      == TYPE_GROUND);
+    ASSUME(GetMoveType(MOVE_ROCK_THROW)    == TYPE_ROCK);
+    ASSUME(GetMoveType(MOVE_BUG_BITE)      == TYPE_BUG);
+    ASSUME(GetMoveType(MOVE_SHADOW_BALL)   == TYPE_GHOST);
+    ASSUME(GetMoveType(MOVE_METAL_CLAW)    == TYPE_STEEL);
+    ASSUME(GetMoveType(MOVE_EMBER)         == TYPE_FIRE);
+    ASSUME(GetMoveType(MOVE_WATER_GUN)     == TYPE_WATER);
+    ASSUME(GetMoveType(MOVE_VINE_WHIP)     == TYPE_GRASS);
+    ASSUME(GetMoveType(MOVE_THUNDER_SHOCK) == TYPE_ELECTRIC);
+    ASSUME(GetMoveType(MOVE_CONFUSION)     == TYPE_PSYCHIC);
+    ASSUME(GetMoveType(MOVE_ICE_BEAM)      == TYPE_ICE);
+    ASSUME(GetMoveType(MOVE_DRAGON_BREATH) == TYPE_DRAGON);
+    ASSUME(GetMoveType(MOVE_BITE)          == TYPE_DARK);
+    ASSUME(GetMoveType(MOVE_FAIRY_WIND)    == TYPE_FAIRY);
+}
+
+SINGLE_BATTLE_TEST("Inverse battle reverses type matchups")
+{
+    u32 species = SPECIES_NONE, move = MOVE_NONE;
+
+    static const u16 monotypeMons[] = {
+        SPECIES_EEVEE,
+        SPECIES_MACHAMP,
+        SPECIES_TORNADUS,
+        SPECIES_ARBOK,
+        SPECIES_DUGTRIO,
+        SPECIES_SUDOWOODO,
+        SPECIES_PINSIR,
+        SPECIES_DUSKULL,
+        SPECIES_REGISTEEL,
+        SPECIES_FLAREON,
+        SPECIES_VAPOREON,
+        SPECIES_LEAFEON,
+        SPECIES_JOLTEON,
+        SPECIES_ESPEON,
+        SPECIES_GLACEON,
+        SPECIES_DRUDDIGON,
+        SPECIES_UMBREON,
+        SPECIES_SYLVEON,
+    };
+
+    static const u16 typeMoves[] = {
+        MOVE_TACKLE,
+        MOVE_KARATE_CHOP,
+        MOVE_GUST,
+        MOVE_POISON_STING,
+        MOVE_MUD_SLAP,
+        MOVE_ROCK_THROW,
+        MOVE_BUG_BITE,
+        MOVE_SHADOW_BALL,
+        MOVE_METAL_CLAW,
+        MOVE_EMBER,
+        MOVE_WATER_GUN,
+        MOVE_VINE_WHIP,
+        MOVE_THUNDER_SHOCK,
+        MOVE_CONFUSION,
+        MOVE_ICE_BEAM,
+        MOVE_DRAGON_BREATH,
+        MOVE_BITE,
+        MOVE_FAIRY_WIND,
+    };
+
+    for (u32 i = 0; i < ARRAY_COUNT(monotypeMons); i++)
+    {
+        for (u32 j = 0; j < ARRAY_COUNT(typeMoves); j++)
+        {
+            PARAMETRIZE { species = monotypeMons[i]; move = typeMoves[j]; }
+        }
+    }
+
+    GIVEN {
+        FLAG_SET(B_FLAG_INVERSE_BATTLE);
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(species);
+    }
+    WHEN {
+        TURN { MOVE(player, MOVE_WORRY_SEED); }
+        TURN { MOVE(player, move); }
+    }
+    SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, move, player);
+        HP_BAR(opponent);
+        if (gTypeEffectivenessTable[GetMoveType(move)][GetSpeciesType(species, 0)] == Q_4_12(2))
+            MESSAGE("It's not very effective…");
+        if (gTypeEffectivenessTable[GetMoveType(move)][GetSpeciesType(species, 0)] == Q_4_12(0.5))
+            MESSAGE("It's super effective!");
+    }
+}
+