Add reviver seed item (untested)

src/modifier/modifier-type.ts

@@ -561,6 +561,9 @@ const modifierTypes = {
 
   SACRED_ASH: () => new AllPokemonFullReviveModifierType('SACRED ASH'),
 
+  REVIVER_SEED: () => new PokemonHeldItemModifierType('REVIVER SEED', 'Revives the holder for 1/2 HP upon fainting',
+    (type, args) => new Modifiers.PokemonInstantReviveModifier(type, (args[0] as Pokemon).id)),
+
   ETHER: () => new PokemonPpRestoreModifierType('ETHER', 10),
   MAX_ETHER: () => new PokemonPpRestoreModifierType('MAX ETHER', -1),
 
@@ -723,6 +726,7 @@ const modifierPool = {
     new WeightedModifierType(modifierTypes.MAX_LURE, 4),
     new WeightedModifierType(modifierTypes.ATTACK_TYPE_BOOSTER, 4),
     new WeightedModifierType(modifierTypes.TM_ULTRA, 5),
+    new WeightedModifierType(modifierTypes.REVIVER_SEED, 3),
     new WeightedModifierType(modifierTypes.CANDY_JAR, 3),
     new WeightedModifierType(modifierTypes.GRIP_CLAW, 2),
     new WeightedModifierType(modifierTypes.HEALING_CHARM, 1),

src/modifier/modifier.ts

@@ -666,6 +666,32 @@ export class PreserveBerryModifier extends PersistentModifier {
   }
 }
 
+export class PokemonInstantReviveModifier extends PokemonHeldItemModifier {
+  constructor(type: ModifierType, pokemonId: integer, stackCount?: integer) {
+    super(type, pokemonId, stackCount);
+  }
+
+  matchType(modifier: Modifier) {
+    return modifier instanceof PokemonInstantReviveModifier;
+  }
+
+  clone() {
+    return new PokemonInstantReviveModifier(this.type, this.pokemonId, this.stackCount);
+  }
+
+  apply(args: any[]): boolean {
+    const pokemon = args[0] as Pokemon;
+
+    pokemon.scene.unshiftPhase(new PokemonHealPhase(pokemon.scene, pokemon.getBattlerIndex(), Math.max(Math.floor(pokemon.getMaxHp() / 2)), getPokemonMessage(pokemon, ` was revived\nby its ${this.type.name}!`), false));
+
+    return true;
+  }
+
+  getMaxStackCount(): integer {
+    return 10;
+  }
+}
+
 export abstract class ConsumablePokemonModifier extends ConsumableModifier {
   public pokemonId: integer;