How to Fish: How to Beat the Mutated Bowhead Whale (Lava Whale Final Boss)

The Mutated Bowhead Whale is the final boss of How to Fish, the physics-driven fishing-and-shooting game from Dazed Games. It only appears on the fifth island, the Volcano, and it is the single fight in the run that can actually stop you. You do not walk into it directly. You first catch and kill a regular Bowhead Whale, then throw that carcass into the volcano to spawn the mutated, lava-covered version.

Quick answer: Bring a fully upgraded assault rifle and a large stock of lava-cooked fish. Give the hazmat scientist five fish for whale bait, catch and kill the regular whale, throw it into the volcano, then drop to the military base and fight the lava whale through both phases while healing on every hit. Loot the Whale Fin and hand it to the scientist for the RHIB keys.

What you need before the fight

This boss is won during preparation, not during the fight itself. A couple of clean hits from the mutated whale can kill you, so raw damage output matters less than keeping your health topped off and never standing still. Treat the regular whale and the lava whale as one continuous encounter, because there is no chance to restock once the final boss is live.

Prep item	Why it matters
Fully upgraded assault rifle	Your main damage source for both whales. Get every available upgrade before summoning.
Laser and suppressor attachments	Fitting the full attachment set gives steady hip-fire accuracy and unlocks the Fully equipped achievement.
Lava-cooked fish (large stock)	Your only healing. Volcano lava cooks at a flat 1.5x value with no timing window.
Spare cooked fish on the ground	Drop a pile near the military camp so you can refill between phases.
Dynamite	Blows up four or five fish at once, which is the fastest way to gather both food and the fish you hand to the scientist.

Note: You need far more healing than you think. Fill your inventory with cooked fish and leave extra piles near the base, since eating on every exchange is what carries the fight.

Spawn the lava whale: the whale-into-volcano sequence

The scientist in the yellow hazmat suit is your military contact on the Volcano island. There is no separate creature to hunt down first. The mutated whale is created by feeding a beaten regular whale to the volcano.

Give the hazmat scientist any five fish. Throwing Dynamite into the water and scooping up the results is the quickest way to gather them.

Take the whale bait he hands you in return. Fit it to your fishing rod.

Reel in and kill the regular Bowhead Whale. It charges across the arena and launches into the sky before slamming down on your position, so run the moment it shoots upward, then dodge, shoot, and eat to heal. This version is far weaker than the mutated one.

Pick up the dead whale and carry it to the top of the volcano using the wooden planks. Equip the carcass and throw it into the lava. This is what spawns the Mutated Bowhead Whale.

Player at the volcano edge looking down at the glowing island as the giant whale looms overhead — Throwing the whale carcass into the volcano from the edge is what summons the mutated version. Image credit: Dazed Games / via @PazarGamingGuides

Drop down to the military base immediately. The flat terrain there is easier to fight on, and it is where you should have already stashed your extra cooked fish.

Beat the Mutated Bowhead Whale in both phases

There is no clever trick to this fight. It is a stamina test. Keep your distance, pour steady assault-rifle fire into the boss whenever it is not mid-attack, and heal every single time you take damage rather than waiting until you are low. The ground is as dangerous as the whale itself.

First-person rifle fire hitting the Mutated Bowhead Whale during phase one with an explosion visible — Phase one: strafe, keep firing between the whale’s attacks, and heal after every hit. Image credit: Dazed Games / via @PazarGamingGuides

Attack	How to respond
Roll	Hold your distance and strafe around it in a circle.
Stomp	Move out from under it the instant it winds up.
Lava pools	Watch the floor and dodge the pools as carefully as the boss.
Lava meteorites	Keep moving across the arena so the shots miss.
Sky launch (phase 2)	Reposition as it rises, then avoid the stomp it lands with.

Phase two is where most runs fall apart. The whale becomes far more aggressive, stomps almost constantly, and periodically leaps into the sky to rain attacks down on your position. Keep moving and reposition the moment it launches. Constant circular, semi-random movement is what keeps you out of the projectile lines while you chip its health bar down.

Combat HUD targeting the Mutated Bowhead Whale with its health bar partly depleted in phase two — Phase two adds far more frequent projectiles and near-constant stomps, so never stand still. Image credit: Dazed Games / via @PazarGamingGuides

Do not try to escape the arena by boat. Pulling the whale too far from the volcano despawns it and resets the whole fight. You can make enough space to read its next move, but do it inside the intended encounter area rather than sailing away.

Co-op turns this into the manageable fight it is designed to be. One player can hold the boss’s attention while the other works a firing line, and being able to revive each other means a single mistake no longer loses the run. The army tent on the island makes solid cover for one player while the other posts up on the opposite side of the shore.

Confirm the kill and hand in the Whale Fin

You know the fight is over when the on-screen notification reads “New Creature Caught: Mutated Bowhead Whale.” The boss drops a Whale Fin on death, but that item alone does not end the game. You still have to return it to the scientist.

Rifle aimed at the glowing whale as the New Creature Caught notification confirms the kill — The “New Creature Caught” prompt confirms the Mutated Bowhead Whale is dead. Image credit: Dazed Games / via @PazarGamingGuides

Pick up the Whale Fin the boss leaves behind.

Carry it back to the hazmat scientist and hand it over. He responds with the keys to the military boat, saying “great, take these keys if you want to head home.”

Rocky shoreline and open ocean with the weapon hotbar visible while returning to the boat — Returning along the shore to the RHIB after collecting the keys from the scientist. Image credit: Dazed Games / via @PazarGamingGuides

Board the RHIB and start it. The military boat takes you to the mainland and rolls the ending credits, which also unlocks the We are so back achievement for finishing the game. Your existing save keeps every purchase and weapon upgrade if you want to continue for collection cleanup afterward.

Killing the boss with your bare hands (Handyman)

If you are chasing the Handyman achievement, “defeat the final boss with your bare hands,” only the killing blow has to be a punch, not the whole fight. Fight the lava whale normally with the assault rifle, then chip its health down to the thinnest sliver you dare before swapping to fists for the final hit. Brass knuckles do not count, so it must be bare hands.

Because you are eyeballing that last bit of health, expect to overshoot and accidentally finish it with the rifle a few times, then just re-run the fight. Have full health before you attempt the punch, since one hit at close range can otherwise kill you. In co-op it is much easier, and if any player in the lobby lands the correct killing blow, everyone earns the achievement.