Hullbreaker

Hullbreakers are rare, gigantic neutral aquatic mobs found in the Abyssal Chasm. They are formidable predators that attack glowing mobs and submarines with their floodlights on.

Cave Compendium Entry

"The Hullbreaker is a colossal fish over fifteen blocks long. Being a predator adapted to hunt exclusively in dark waters, it hunts by seeking out any glowing entity. It quickly makes a kill by using its massive teeth to bite prey or its head as a battering ram to smash them. The easiest way to avoid the wandering eyes of a Hullbreaker is to stop emitting light, and to remove any glowing effect or entity. Hullbreakers always investigate possible prey items before attacking, circling them multiple times whilst its many body lights begin to flash rapidly. In the almost unheard of chance that one is defeated in combat, it will spew out what it has eaten before dying. This includes common items like ink sacs, but can also be remains of Submarines such as the Enigmatic Engine. If a hullbreaker is detected whilst one is in a submarine, caution must be taken to immediately turn off any and all floodlights until the beast passes..."

- Dr. Prof. Alexander Caverns, PhD.

Spawning

Hullbreakers can spawn anywhere in the Abyssal Chasm.

Drops

On death

Item	Roll Chance	Quantity
Enigmatic Engine	100%	1
Immortal Embryo	100%	1
Sea Glass Shards	100%	2-5
Copper Ingot	100%	2-8
Scrap Metal	100%	2-4

⚠️ Contrary to their Cave Compendium entry, Hullbreakers do not drop Ink Sacs.

Behavior

Hullbreakers target any mobs that naturally emit a bright glow, any mobs that are affected by Glowing, and any players inside submarines that have their floodlights on. Submarines that catch the interest of a Hullbreaker will start emitting sonar pings and pulsing their control panel.

Hullbreakers track their interest in a target as a number from 0 to 6.

1. Once a Hullbreaker notices a target, it immediately adds 5 interest and pulses its its eyes and photophores - if within 17 blocks of its target, it will also stare at them while slowly tilting its head from side to side for 3 seconds.
2. After noticing a target, a Hullbreaker will then enter an inspection phase where it circles its target for at least 6 seconds before staring at them again, repeating the phase. If it can progress through an equivalent of 2 inspection phases, it will add 1 interest.
3. Once reaching 6 interest, it will start attacking its target directly.
4. If a player or another mob attacks a Hullbreaker's torso, it will immediately add 6 interest - as a multi-part mob, a Hullbreaker will not react if hit anywhere else.
5. If its target escapes, it will immediately lose all its interest.

Default glowing prey

Below are the mobs that Hullbreakers will target on sight, regardless of whether they are affected by Glowing.

Mob	Swims?	Spawns in Abyssal Chasm?	Notes
Glow Squid	Yes	Yes
Blaze	No	No	Blazes take damage in water, and thus often die before the Hullbreaker can attack.
Enderman	No	No	Endermen take damage and automatically teleport on contact with water, and thus are rarely ever targeted by a Hullbreaker.
Allay	No	No	Allays avoid water at all costs, and thus rarely are ever targeted by a Hullbreaker.
Magma Cube	No	No
Phantom	No	No	Unlike most flying mobs, Phantoms will fly into water, letting them be easily targeted by a Hullbreaker.
Warden	No	No
Teletor	No	No
Magnetron	No	No	Magnetrons bounce up and down on the water's surface, constantly resetting the Hullbreaker's interest and thus rarely ever getting attacked by it.
Boundroid	No	No	Boundroids’ winches bounce up and down on the water's surface, but they themselves float in place, letting them be easily targeted by a Hullbreaker.
Notor	No	No
Nucleeper	No	No
Radgill	Yes	No
Raycat	No	No
Gossamer Worm	Yes	Yes
Tremorzilla	Yes	Depends	A Tremorzilla can spawn in the Abyssal Chasm if its egg is hatched there.

When within 8 blocks of its target, a Hullbreaker will usually bite them. Occasionally, it may lower its head to tackle them, breaking any blocks with a blast resistance of 15 or less in the way. Hullbreakers are also unable to break barriers, bedrock, command blocks, End portal blocks, End gateway blocks, jigsaw blocks, lights, moving pistons, reinforced deepslate, structure blocks, and Volcanic Cores. If /gamerule mobGriefing is false, a Hullbreaker will be unable to break any kind of block with its tackle.

Dying Hullbreakers wail while spitting out their drops - on land, they will groan as they expel drops instead. Items dropped from Hullbreakers have a glowing white outline, similarly to mobs affected with Glowing.

Since they are classified as creatures rather than monsters, Hullbreakers persist on Peaceful difficulty. However, they will never attack players, only inspecting them if they are inside submarines that have their floodlights on.

Resistances and weaknesses

Hullbreakers take 35% less damage from projectiles that hit its torso, and 65% less damage from those that hit anywhere else.

As inhabitants of the Abyssal Chasm, Hullbreakers do not sink in Muck. Due to their immense size, they also cannot be possessed by the Totem of Possession.

Hullbreakers cannot survive outside of water. On dry land, they will lay on their sides and emit guttural growls, suffocating for 2 damage every second after 15 seconds.

History

1.0.0	Introduced.
1.1.0	Hullbreakers now take less damage from projectiles. Hullbreakers now drop an Immortal Embryo upon death.
1.1.4	Fixed Hullbreakers getting crowded out of spawn pools by other mods.
2.0.0	Hullbreakers no longer attack themselves if given the Glowing effect.

Trivia

• Hullbreakers are classified as underground water creatures, similarly to Glow Squids.
• Hullbreakers will not make sounds when attacking targets unless they successfully hit them.

Gallery

• 

  A Hullbreaker swimming with some Glow Squids.
• 

  A Hullbreaker vomiting the contents of its stomach on death.
• 

  A Hullbreaker attacking Deep Ones.
• 

  A Hullbreaker investigating a Submarine.