Is There an Achievement for Completing the Terraria Bestiary?

Yes — Terraria does reward players for filling out the Bestiary, and there's a specific achievement tied to completing it. If you've been methodically hunting down every enemy, critter, and boss just to see that progress bar hit 100%, the game does acknowledge the effort.

What Is the Terraria Bestiary?

The Bestiary is an in-game encyclopedia introduced in Terraria version 1.4 (Journey's End). It automatically logs every enemy, NPC, critter, and boss you encounter during your playthrough. Each entry fills in with flavor text, combat stats, and behavioral notes as you interact with or observe that entity enough times.

The Bestiary tracks hundreds of entries across all biomes, events, and game modes. Some entries unlock after a single encounter; others require defeating a mob multiple times before the full entry appears.

The Achievement: Obtain the Zoologist NPC and Complete the Bestiary 🏆

There are two distinct achievements connected to the Bestiary system:

"Zoologist" Achievement

This achievement unlocks when you fill the Bestiary to 10% — which is the condition needed to get the Zoologist NPC to move into your town. The Zoologist sells vanity items, critter-related accessories, and the Leather Whip, making her one of the more useful NPCs for certain playstyles. This achievement is relatively early and accessible even in a fresh playthrough.

"Infinity +1 Sword" Achievement — Wait, Wrong One

The achievement specifically tied to fully completing the Bestiary is called "To Be Continued…" — though it's worth double-checking in-game, as Steam achievement names and in-game labels occasionally differ slightly by platform or version. On Steam, the achievement tied to 100% Bestiary completion is listed and does count toward your overall achievement progress for the game.

What Does 100% Bestiary Completion Actually Require?

This is where the real complexity lives. Completing the Bestiary means encountering every entity in the game, which includes:

• All biome-specific enemies — Desert, Jungle, Dungeon, Underworld, etc.
• All event enemies — Blood Moon, Goblin Army, Solar Eclipse, Pumpkin Moon, Frost Moon, Martian Madness, and more
• All bosses — including optional and hardmode bosses
• Critters — passive animals like Butterflies, Frogs, Goldfish, and Squirrels that appear in specific biomes or conditions
• Town NPCs — yes, the Bestiary logs your NPCs too
• Hardmode-exclusive enemies — mobs that only spawn after you've defeated the Wall of Flesh

Entries That Are Easy to Miss

Does Difficulty or Game Mode Affect the Achievement?

Game mode matters — but not always in the way you'd expect.

• Journey Mode gives you access to most content but some mob behavior differs, which can affect spawn conditions.
• Classic, Expert, and Master Mode share the same Bestiary pool for most entries, but Expert and Master Mode introduce some unique enemies and modifiers worth noting.
• Hardcore characters are a risk factor — dying permanently means starting over with a new character, though your world retains its state.

One important note: the Bestiary is tied to the character file, not the world. If you switch characters mid-playthrough, your Bestiary progress doesn't transfer. This trips up a surprising number of players who use multiple characters across different worlds.

Platform Differences Worth Knowing 🎮

• On PC (Steam), achievements are tracked through Steam and visible in your library.
• On console versions (PlayStation, Xbox, Nintendo Switch), achievements or trophies follow the same general Bestiary milestones but may have slightly different naming conventions.
• Mobile has its own achievement system, and not all PC achievements have been mirrored identically across every patch cycle on mobile.

If you're playing on a platform other than PC, it's worth checking the platform's specific trophy/achievement list to confirm the exact unlock condition listed there.

How Long Does Completing the Bestiary Take?

There's no single answer — it depends heavily on how you play. A focused playthrough targeting Bestiary completion from the start will look very different from a casual run where you're filling gaps over dozens of hours. Players who skip certain events (like never triggering a Pumpkin Moon or Frost Moon) will find significant chunks of their Bestiary missing well into endgame.

Some critters and rare spawns require patience even when you know where to look. Underground critters in particular can go unnoticed for an entire playthrough if you're moving quickly through caves rather than stopping to observe.

The total number of Bestiary entries also varies slightly depending on which mods you have active — though modded entries don't count toward the vanilla achievement.

What the Gap Looks Like in Practice

Whether the achievement is within reach depends on where you are in your playthrough, which game mode you chose, how many events you've triggered, and whether you've been playing with a consistent character. Two players both describing themselves as "almost done" with the Bestiary can be in very different situations once you look at which specific entries are missing.