diff --git a/src/data/pokemon-species.ts b/src/data/pokemon-species.ts
index c0ca9bf4b62..c9d49f29440 100644
--- a/src/data/pokemon-species.ts
+++ b/src/data/pokemon-species.ts
@@ -68,10 +68,7 @@ export const normalForm: Species[] = [
  * @param species The species to fetch
  * @returns The associated {@linkcode PokemonSpecies} object
  */
-export function getPokemonSpecies(species: Species | Species[] | undefined): PokemonSpecies {
-  if (!species) {
-    throw new Error("`species` must not be undefined in `getPokemonSpecies()`");
-  }
+export function getPokemonSpecies(species: Species | Species[]): PokemonSpecies {
   // If a special pool (named trainers) is used here it CAN happen that they have a array as species (which means choose one of those two). So we catch that with this code block
   if (Array.isArray(species)) {
     // Pick a random species from the list
@@ -914,7 +911,8 @@ export default class PokemonSpecies extends PokemonSpeciesForm implements Locali
 
     for (const weight of evolutionPool.keys()) {
       if (randValue < weight) {
-        return getPokemonSpecies(evolutionPool.get(weight)).getSpeciesForLevel(level, true, forTrainer, strength, currentWave);
+        // TODO: this entire function is dumb and should be changed, adding a `!` here for now until then
+        return getPokemonSpecies(evolutionPool.get(weight)!).getSpeciesForLevel(level, true, forTrainer, strength, currentWave);
       }
     }
 
diff --git a/test/mystery-encounter/encounters/uncommon-breed-encounter.test.ts b/test/mystery-encounter/encounters/uncommon-breed-encounter.test.ts
index ab50666ab3d..1bdc45348d6 100644
--- a/test/mystery-encounter/encounters/uncommon-breed-encounter.test.ts
+++ b/test/mystery-encounter/encounters/uncommon-breed-encounter.test.ts
@@ -116,7 +116,7 @@ describe("Uncommon Breed - Mystery Encounter", () => {
       await game.runToMysteryEncounter(MysteryEncounterType.UNCOMMON_BREED, defaultParty);
 
       const config = game.scene.currentBattle.mysteryEncounter!.enemyPartyConfigs[0];
-      const speciesToSpawn = config.pokemonConfigs?.[0].species.speciesId;
+      const speciesToSpawn = config.pokemonConfigs?.[0].species.speciesId!;
 
       await runMysteryEncounterToEnd(game, 1, undefined, true);
 
@@ -143,7 +143,7 @@ describe("Uncommon Breed - Mystery Encounter", () => {
       await game.runToMysteryEncounter(MysteryEncounterType.UNCOMMON_BREED, defaultParty);
 
       const config = game.scene.currentBattle.mysteryEncounter!.enemyPartyConfigs[0];
-      const speciesToSpawn = config.pokemonConfigs?.[0].species.speciesId;
+      const speciesToSpawn = config.pokemonConfigs?.[0].species.speciesId!;
 
       await runMysteryEncounterToEnd(game, 1, undefined, true);