The Halibut Harpoon is a Stage 10 piece of gear that swaps between a harpoon gun and a normal fishing rod at the press of a button. Earning it takes a full questline from the Dr. Monty NPC, and once it is yours, a four-part Mastery track layers on more objectives that arrive as riddles instead of plain instructions. Every Mastery goal can be solved, and the final reward is the Terminus Enhancement plus the Flak Krakenling skin.
Quick answer: Answer Dr. Monty’s three riddles with Hubbermeisterchen, 13,388.82 C$, and Orange, finish both Pufferfish quests to claim the rod, then clear the four Mastery riddles ending with the Terminus Challenge.
Requirements before you start
The rod sits behind a hard gate. You need to be Level 1000 and have 50,000,000 C$ ready to claim it once Dr. Monty hands it over. The Mastery track was added in the Version 2.04 Second Anniversary update, so you must already own the Halibut Harpoon from his questline before the Mastery quests appear.
For every Mastery step, keep the Halibut Harpoon in its rod mode, not the default Harpoon mode. Harpoon mode does not count toward these objectives, and progress you make with it will not stick.
Find Dr. Monty and answer his three riddles
Dr. Monty hides in a secret laboratory on the northernmost edge of The Deep, inside the Outer Deep. Get a single riddle wrong and the conversation ends, you respawn at your set point, and you have to travel all the way back. Line up the answers before you talk to him.
| Question | Answer |
|---|---|
| The goggobites gather for what? | Hubbermeisterchen |
| What is the base value of a Sparkling Shiny Aether Pufferfish? | 13,388.82 C$ |
| What is my favorite color? | Orange |
Dr. Monty’s two Pufferfish quests
With the riddles cleared, Dr. Monty hands over two quest sets. Prepare bait and rods ahead of time so you are not backtracking for a single weather window.
Quest 1: Catch seven Pufferfish species
Catch and return 10 of each of the seven Pufferfish below. The Carrot Pufferfish needs rainy Spring and the Pufferflute needs a clear Autumn day, so plan those two windows rather than waiting on luck.
| Fish (x10) | Location | Bait | Conditions |
|---|---|---|---|
| Pufferfish | Roslit Bay / The Ocean | Seaweed | Summer, any weather, any time |
| Flying Pufferfish | Above The Clouds | Seaweed | Summer, any weather, any time |
| Blight Pufferfish | Toxic Grove | Weird Algae | Any season, weather, time |
| Pufferflute | Crystal Cove | Flakes | Autumn, clear, day |
| Pyrite Pufferfish | Volcanic Vents | Shrimp | Autumn, any weather, night |
| Carrot Pufferfish | Carrot Garden | None | Spring, rain, any time |
| Mustard | The Ocean | Seaweed | Summer, rain, any time |
Quest 2: Perfect Catch mutated Pufferfish
Every catch here must be a Pufferfish, a Perfect Catch, and carry a specific mutation. You need 10 of each. The fastest route is to equip the rod tied to each mutation, then land clean Perfect Catches until the counter fills. If a step refuses to tick up, the catch either was not a Perfect Catch or did not carry the exact mutation.
| Mutation (x10) | Rod to equip |
|---|---|
| Wrath | Rod of The Zenith or Dead Man’s Rod |
| Rotting | Splitbranch Twig |
| Lost | The Lost Rod |
| Abyssal | Abyssal Specter Rod or Rod of the Depths |
| Celestial | Celestial Rod |
| Crystalized | Crystalized Rod |
| Aurulent | Auric Rod |
| Heavenly | Heaven’s Rod |
| Sunken | Sunken Rod |
| Greedy | Scurvy Rod or Rod of the Eternal King |
| Lucid | Lucid Rod |
| Lunar | Event Horizon Rod or Astral Rod |
| Atlantean | Trident Rod |
| Phantom | Eidolon Rod |
| Bellona’s Fury | Bellona’s Waraxe |
| Mastered | Ruinous Oath |
| Sandy | Sand Castle Caster |
| Rainbow Cluster | Rainbow Cluster Rod |
| Honey | Sweet-Stinger |
| Solarblaze | Fang of the Eclipse or Wicked Fang Rod |
| Sanguine | Sanguine Spire |
| Tainted | Bloomspire: Twisted Toxins |
| Tidal | Rod of the Forgotten Fang |
| Brined | Brine-infused Rod |
| Mythical | Mythical Rod |
Return every required fish to Dr. Monty as you go. Once both quest sets read as finished, he awards the Halibut Harpoon. Because it is a harpoon gun, it lands in your Equipment Bag under the Harpoon Guns section instead of the rod list. Open that section and equip it to use.
All four Mastery riddles and solutions
The Mastery track holds four objectives. The first three are worded as riddles and each drops a Terminus Fragment, and you need all three fragments to attempt the final step. Clear the riddles first.
| Quest | Objective | Reward |
|---|---|---|
| 500 Suggestions | Catch 5 anniversary event fish with a qualifying mutation | Bait Enhancement unlock, Terminus Fragment x1 |
| These are Pufferfish? | Catch all three Halibut types with the Hadal mutation | Dreaming Puffers Supporter Halo, Title, Terminus Fragment x1 |
| They fly now? | Catch one Hadal Wyvern | Pufferfish Balloon x1, Terminus Fragment x1 |
| Terminus | Complete the Terminus Challenge | Terminus Lantern, Terminus Enhancement |
500 Suggestions
The riddle reads “I’m blue on special occasions.” (0/5). Catch 5 Fisch 2nd Anniversary Event fish carrying the Hadal, Thalassic, or Bathyal mutation using the Halibut Harpoon. You can fish around the Birthday Cake area, catch global event spawns, or fish an Anniversary Pool. Clearing it lets Limited and Special bait be used in the Halibut Harpoon’s Enhancement and grants the first Terminus Fragment.
These are Pufferfish?
The riddle reads “We’re making up rules, so the rod requirements should be based on its appearance?” (0/3). Catch all three Halibut in the game, each with the Hadal mutation, using only the Halibut Harpoon in rod mode. The reward is the Dreaming Puffers Supporter Halo, the Hadopelagic Title, and a Terminus Fragment.
| Halibut (Rarity) | Location | Bait | Conditions |
|---|---|---|---|
| Halibut (Rare) | The Ocean / Deep Ocean | Squid | Spring or Summer, rain, any time |
| Greenland Halibut (Rare) | Boreal Pines | Worm | Winter, any weather, any time |
| Hoarfrost Halibut (Legendary) | Challenger’s Deep | Fish Head | Winter, clear, day |
For the regular Halibut, the twin wooden docks at Boreal Pines around coordinates -4340.6, -214.3, 2197.8 are a reliable spot for the Greenland variant. Harpoon Mode does not count here, so keep the rod in standard fishing mode.
They fly now?
The riddle reads “Bring the depths to those that fly the highest!” (0/1). Catch one Wyvern with the Hadal mutation. The Wyvern (Exotic) spawns Above The Clouds during rain, any season or time, and bites on Truffle Worm or Starlight Worm. The Long enchant on the Halibut Harpoon helps against it by raising Resilience, Line Distance, and Progress Speed. This step gives a Pufferfish Balloon and the third Terminus Fragment.
Terminus
The final step reads “Complete the Terminus Challenge with Halibut Harpoon without any Companions or Gloves equipped” (0/1). Combine all three Terminus Fragments in your inventory to craft the Terminus item, then activate it while holding the Halibut Harpoon to enter the mini-game. You must catch 25 Hunt Fish back-to-back in a fixed order without breaking the streak. Winning awards the Terminus Lantern.
Having any Glove or Companion equipped invalidates the attempt. Unequip both before you activate the Terminus item.
Terminus Challenge fish order
The 25 fish arrive in a set sequence. Clearing each minigame moves you to the next, and a single failure ends the run.
- Frostwyrm
- Livyatan
- Scylla
- Plesiosaur
- Colossal Ethereal Dragon
- Ancient Goldwraith
- Bloop Fish
- Wyvern
- Ancestral Pliosaur
- Elder Mossjaw
- Awakened Omnithal
- Profane Leviathan
- Colossus Reef Titan
- Ancient Kraken
- Skeletal Leviathan
- Ancestral Abaia
- Veiled Charybdis
- Photic Terrosunder
- Tidecrasher Archon
- Helios Sunray
- Kerauno Wyrm
- Legionnaire Lamprey
- Styx Angler
- Skolopendra
- Olympian Devil
Terminus Enhancement and completion rewards
Beating the Terminus Challenge unlocks the Terminus Enhancement, which reworks how the rod performs:
- The base +20% Fish Weight becomes a 50% chance for +25% or a 50% chance for +35%.
- Harpoons that land outside the bar now grant 30% of their original progress.
- Initial harpoon delay on Progress Locked fish drops to 1.5 seconds, down from 2 seconds.
- Bait Preservation chance rises to 50%, up from the default 10%.
- Bait rarity passives now apply in Harpoon Mode.
Finishing all four Mastery quests also unlocks the Flak Krakenling skin for the Halibut Harpoon as the completion reward. You can confirm everything is done from the inventory menu under Fishing Rods. Open the Halibut Harpoon and check its mastery interface, where each quest shows its completion state and the Completion Reward lists the Flak Krakenling skin. With the Terminus Challenge cleared and every quest marked complete, the passives are active and the skin is yours to equip.
