Fix: Terastallize Ogerpon and Terapagos with different Tera types

data/abilities.ts

@@ -1167,8 +1167,9 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	embodyaspectcornerstone: {
 		onStart(pokemon) {
-			if (pokemon.baseSpecies.name === 'Ogerpon-Cornerstone-Tera' &&
-				this.effectState.embodied !== pokemon.previouslySwitchedIn) {
+			if (pokemon.baseSpecies.name === 'Ogerpon-Cornerstone-Tera' && pokemon.terastallized &&
+				this.effectState.embodied !== pokemon.previouslySwitchedIn
+			) {
 				this.effectState.embodied = pokemon.previouslySwitchedIn;
 				this.boost({def: 1}, pokemon);
 			}
@@ -1180,8 +1181,9 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	embodyaspecthearthflame: {
 		onStart(pokemon) {
-			if (pokemon.baseSpecies.name === 'Ogerpon-Hearthflame-Tera' &&
-				this.effectState.embodied !== pokemon.previouslySwitchedIn) {
+			if (pokemon.baseSpecies.name === 'Ogerpon-Hearthflame-Tera' && pokemon.terastallized &&
+				this.effectState.embodied !== pokemon.previouslySwitchedIn
+			) {
 				this.effectState.embodied = pokemon.previouslySwitchedIn;
 				this.boost({atk: 1}, pokemon);
 			}
@@ -1193,8 +1195,9 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	embodyaspectteal: {
 		onStart(pokemon) {
-			if (pokemon.baseSpecies.name === 'Ogerpon-Teal-Tera' &&
-				this.effectState.embodied !== pokemon.previouslySwitchedIn) {
+			if (pokemon.baseSpecies.name === 'Ogerpon-Teal-Tera' && pokemon.terastallized &&
+				this.effectState.embodied !== pokemon.previouslySwitchedIn
+			) {
 				this.effectState.embodied = pokemon.previouslySwitchedIn;
 				this.boost({spe: 1}, pokemon);
 			}
@@ -1206,8 +1209,9 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	embodyaspectwellspring: {
 		onStart(pokemon) {
-			if (pokemon.baseSpecies.name === 'Ogerpon-Wellspring-Tera' &&
-				this.effectState.embodied !== pokemon.previouslySwitchedIn) {
+			if (pokemon.baseSpecies.name === 'Ogerpon-Wellspring-Tera' && pokemon.terastallized &&
+				this.effectState.embodied !== pokemon.previouslySwitchedIn
+			) {
 				this.effectState.embodied = pokemon.previouslySwitchedIn;
 				this.boost({spd: 1}, pokemon);
 			}
@@ -4842,6 +4846,13 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 			if (pokemon.baseSpecies.name !== 'Terapagos-Stellar') return;
 			if (this.field.weather || this.field.terrain) {
 				this.add('-ability', pokemon, 'Teraform Zero');
+				if (pokemon.terastallized !== 'Stellar') {
+					if (this.field.weather || this.field.terrain) {
+						// display fail message https://www.youtube.com/watch?v=g-eUP0IrxI0
+						this.hint("Teraform Zero fails to remove the weather and the terrain if Terapagos-Stellar is not Tera-Stellar.");
+					}
+					return;
+				}
 				this.field.clearWeather();
 				this.field.clearTerrain();
 			}

sim/battle-actions.ts

@@ -1928,6 +1928,10 @@ export class BattleActions {
 		if (pokemon.getItem().zMove || pokemon.canMegaEvo || this.dex.gen !== 9) {
 			return null;
 		}
+		if (pokemon.species.baseSpecies === 'Ogerpon' && !['Fire', 'Grass', 'Rock', 'Water'].includes(pokemon.teraType)) {
+			this.battle.hint("Ogerpon can only terastallize into Fire, Grass, Rock or Water types, or the game gets softlocked.");
+			return null;
+		}
 		return pokemon.teraType;
 	}
 
@@ -1946,10 +1950,11 @@ export class BattleActions {
 		pokemon.knownType = true;
 		pokemon.apparentType = type;
 		if (pokemon.species.baseSpecies === 'Ogerpon') {
-			const tera = pokemon.species.id === 'ogerpon' ? 'tealtera' : 'tera';
-			pokemon.formeChange(pokemon.species.id + tera, null, true);
+			let ogerponSpecies = toID(pokemon.species.battleOnly || pokemon.species.id);
+			ogerponSpecies += ogerponSpecies === 'ogerpon' ? 'tealtera' : 'tera';
+			pokemon.formeChange(ogerponSpecies, null, true);
 		}
-		if (pokemon.species.name === 'Terapagos-Terastal' && type === 'Stellar') {
+		if (pokemon.species.name === 'Terapagos-Terastal') {
 			pokemon.formeChange('Terapagos-Stellar', null, true);
 			pokemon.baseMaxhp = Math.floor(Math.floor(
 				2 * pokemon.species.baseStats['hp'] + pokemon.set.ivs['hp'] + Math.floor(pokemon.set.evs['hp'] / 4) + 100

sim/pokemon.ts

@@ -1387,14 +1387,26 @@ export class Pokemon {
 			this.illusion ? this.illusion.species.name : species.baseSpecies;
 		if (isPermanent) {
 			this.baseSpecies = rawSpecies;
-			this.details = species.name + (this.level === 100 ? '' : ', L' + this.level) +
+			let displayedSpeciesName = species.name;
+			if (species.baseSpecies === 'Ogerpon' && this.terastallized && this.teraType !== species.forceTeraType) {
+				switch (this.teraType) {
+				case 'Grass': displayedSpeciesName = 'Ogerpon-Teal-Tera'; break;
+				case 'Water': displayedSpeciesName = 'Ogerpon-Wellspring-Tera'; break;
+				case 'Fire': displayedSpeciesName = 'Ogerpon-Hearthflame-Tera'; break;
+				case 'Rock': displayedSpeciesName = 'Ogerpon-Cornerstone-Tera'; break;
+				}
+			}
+			this.details = displayedSpeciesName + (this.level === 100 ? '' : ', L' + this.level) +
 				(this.gender === '' ? '' : ', ' + this.gender) + (this.set.shiny ? ', shiny' : '');
 			let details = (this.illusion || this).details;
 			if (this.terastallized) details += `, tera:${this.terastallized}`;
 			this.battle.add('detailschange', this, details);
 			if (!source) {
 				// Tera forme
 				// Ogerpon/Terapagos text goes here
+				if (species.baseSpecies === 'Ogerpon' && this.terastallized && this.teraType !== species.forceTeraType) {
+					this.battle.hint(`Ogerpon terastallized into ${species.name}, but it has taken the appearance of ${displayedSpeciesName} due to its tera type being ${this.teraType}.`);
+				}
 			} else if (source.effectType === 'Item') {
 				this.canTerastallize = null; // National Dex behavior
 				if (source.zMove) {

sim/team-validator.ts

@@ -682,7 +682,7 @@ export class TeamValidator {
 				set.hpType = type.name;
 			}
 		}
-		if (species.forceTeraType) {
+		if (species.forceTeraType && ruleTable.has('obtainablemisc')) {
 			set.teraType = species.forceTeraType;
 		}
 		if (set.teraType) {

test/sim/misc/ogerpon.js

@@ -20,4 +20,80 @@ describe(`[Hackmons] Ogerpon`, function () {
 		battle.makeChoices('switch 2', 'auto');
 		assert.equal(ogerpon.ability, 'embodyaspectteal', `Ogerpon's ability should be Embody Aspect after switching out`);
 	});
+
+	it(`can't Terastallize into a type other than Fire, Grass, Rock or Water`, function () {
+		battle = common.gen(9).createBattle([[
+			{species: 'ogerponwellspringtera', ability: 'embodyaspectwellspring', moves: ['sleeptalk'], teraType: 'Electric'},
+		], [
+			{species: 'silicobra', moves: ['stealthrock']},
+		]]);
+		assert.throws(() => battle.makeChoices('move sleeptalk terastallize', 'auto'), "/Can't move: Ogerpon can't Terastallize./");
+	});
+
+	// https://www.smogon.com/forums/threads/ogerpon-teal-tera-tera-can-exist.3742851/post-10132811
+	it(`can Terastallize to a type other than its mask type`, function () {
+		battle = common.gen(9).createBattle([[
+			{species: 'ogerponwellspring', ability: 'waterabsorb', moves: ['ivycudgel'], teraType: 'Rock'},
+		], [
+			{species: 'seismitoad', ability: 'waterabsorb', moves: ['stealthrock']},
+		]]);
+		const ogerpon = battle.p1.active[0];
+		battle.makeChoices('move ivycudgel terastallize', 'auto');
+		assert.species(ogerpon, 'Ogerpon-Wellspring-Tera');
+		assert.equal(ogerpon.ability, 'embodyaspectwellspring');
+		assert.statStage(ogerpon, 'spd', 1);
+		assert.equal(ogerpon.getTypes().join(''), 'Rock');
+		assert.fullHP(battle.p2.active[0]);
+		assert(battle.log.includes('|detailschange|p1a: Ogerpon|Ogerpon-Cornerstone-Tera, F, tera:Rock') >= 0);
+	});
+
+	// https://www.smogon.com/forums/threads/ogerpon-teal-tera-tera-can-exist.3742851/post-10132811
+	it(`Tera form can Terastallize`, function () {
+		battle = common.gen(9).createBattle([[
+			{species: 'ogerponwellspringtera', ability: 'embodyaspectwellspring', moves: ['ivycudgel'], teraType: 'Water'},
+		], [
+			{species: 'seismitoad', ability: 'waterabsorb', moves: ['stealthrock']},
+		]]);
+		const ogerpon = battle.p1.active[0];
+		battle.makeChoices('move ivycudgel terastallize', 'auto');
+		assert.species(ogerpon, 'Ogerpon-Wellspring-Tera');
+		assert.equal(ogerpon.ability, 'embodyaspectwellspring');
+		assert.statStage(ogerpon, 'spd', 1);
+		assert.equal(ogerpon.getTypes().join(''), 'Water');
+		assert.fullHP(battle.p2.active[0]);
+		assert(battle.log.includes('|detailschange|p1a: Ogerpon|Ogerpon-Wellspring-Tera, F, tera:Water') >= 0);
+	});
+
+	// https://www.smogon.com/forums/threads/ogerpon-teal-tera-tera-can-exist.3742851/post-10132811
+	it(`Tera form can Terastallize to a type other than its mask type`, function () {
+		battle = common.gen(9).createBattle([[
+			{species: 'ogerponwellspringtera', ability: 'embodyaspectwellspring', moves: ['ivycudgel'], teraType: 'Rock'},
+		], [
+			{species: 'seismitoad', ability: 'waterabsorb', moves: ['stealthrock']},
+		]]);
+		const ogerpon = battle.p1.active[0];
+		battle.makeChoices('move ivycudgel terastallize', 'auto');
+		assert.species(ogerpon, 'Ogerpon-Wellspring-Tera');
+		assert.equal(ogerpon.ability, 'embodyaspectwellspring');
+		assert.statStage(ogerpon, 'spd', 1);
+		assert.equal(ogerpon.getTypes().join(''), 'Rock');
+		assert.fullHP(battle.p2.active[0]);
+		assert(battle.log.includes('|detailschange|p1a: Ogerpon|Ogerpon-Cornerstone-Tera, F, tera:Rock') >= 0);
+	});
+
+	// https://www.smogon.com/forums/threads/ogerpon-teal-tera-tera-can-exist.3742851/post-10132811
+	it(`Embody Aspect should not activate unless the user is Terastallized`, function () {
+		battle = common.gen(9).createBattle([[
+			{species: 'ogerponwellspringtera', ability: 'embodyaspectwellspring', moves: ['sleeptalk'], teraType: 'Water'},
+		], [
+			{species: 'silicobra', moves: ['stealthrock']},
+		]]);
+		const ogerpon = battle.p1.active[0];
+		battle.makeChoices();
+		assert.species(ogerpon, 'Ogerpon-Wellspring-Tera');
+		assert.statStage(ogerpon, 'spd', 0);
+		battle.makeChoices('move sleeptalk terastallize', 'auto');
+		assert.species(ogerpon, 'Ogerpon-Wellspring-Tera');
+		assert.statStage(ogerpon, 'spd', 1);
+	});
 });

test/sim/misc/terapagos.js

@@ -39,4 +39,18 @@ describe(`Terapagos`, function () {
 		const terapagos = battle.p1.active[0];
 		assert.species(terapagos, 'Terapagos-Terastal');
 	});
+
+	it(`[Hackmons] can Terastallize into other types, but Teraform Zero fails`, function () {
+		battle = common.createBattle([[
+			{species: 'terapagos', ability: 'terashift', moves: ['sleeptalk'], teraType: 'Fire'},
+		], [
+			{species: 'kyogre', ability: 'drizzle', moves: ['sleeptalk']},
+		]]);
+		const terapagos = battle.p1.active[0];
+		battle.makeChoices('move sleeptalk terastallize', 'auto');
+		assert.species(terapagos, 'Terapagos-Stellar');
+		assert.equal(terapagos.terastallized, 'Fire');
+		assert(battle.log.includes('|-ability|p1a: Terapagos|Teraform Zero'), 'Teraform Zero should activate');
+		assert.equal(battle.field.weather, 'raindance', 'Teraform Zero should fail');
+	});
 });