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Crabularva is a mid-boss in Blaster Master Zero, appearing in Area 2. It later reappears in Area 9, where it can be fought twice. As the name implies, they are larvae of Crabullus.

Physical Appearance[]

Crabularva has a green head with three horns, green pincer mandibles, and four black eyes. Its body is composed of three additional segments with a tail at the end, although this is not usually visible.

General Information[]

Crabularva initially appear as the second mid-boss in the Residential Area. Defeating them normally grants the Laser Shot, allowing SOPHIA III to charge and shoot a laser that penetrates walls and enemies without using energy. In Destroyer Mode, defeating them grants the Shield Mine Sub-weapon, allowing SOPHIA III to drop a mine that transforms into an energy shield, blocking enemy projectiles and doing contact damage to enemies.

Crabularva appear 2 more times in the Alternate Dimension Area, with both occurrences being connected to the Hard Shell re-fight in the Key 5 dungeon. However, only the Crabularva lair connected to the top of Hard Shell's Area 9 lair leads to Spark Salamander and the key. (The bottom lair is a dead-end which is only useful for its post-boss Life and Gun capsules.)


Crabularva is composed of two individuals, with the arena having five acid puddles: one near each corner, and one in the middle. Ripples will appear in the two puddles where the Crabularva will surface. When their heads surface from the puddles, they will each be facing a different direction; usually one will be looking at the player. They will then shoot acid from their mouths, which create damaging puddles on the ground; once the puddles form, the Crabularva recede back into their puddles to reappear in different positions.


This mutant attacks while hidden in acid...but, if you do something to startle it, it may come out.
— Eve

Crabularva’s attacks are easy to avoid due to the amount of time given between surfacing and spitting. They can also be easily approached because they usually do not move around aside from popping their heads out of puddles, with the rippling effect appearing long enough for the player to act accordingly.

Using Reflect, Crabularva’s attacks can be effectively nullified, however, this doesn’t serve as a particularly great offensive option.

Crabularva are weak to Diffusion, causing the one being attacked to be stunned for a period of time and taking more damage than usual. Using a Grenade Bomb on one of the rippling puddles right before a Crabularva is about to surface will cause it to be shot out of the puddle and onto the ground, where it will wiggles around before making its way to a nearby puddle; this prevents it from attacking and leaves it vulnerable for a longer period of time than when it just sticks its head up. (Shovel Knight can similarly fish up surfacing Crabularvae with his Fishing Rod, albeit with tighter timing.) Using Grenade Bombs to extend the vulnerability of Crabularva alongside Diffusion’s extra damage and stun can make quick work of Crabularva, defeating them in less than 15 seconds (in two “rounds”).

Despite Diffusion beings its weakness, Striker is slightly more effective (even without using Grenade Bombs), as it hits both targets simultaneously and has a high rate of fire at close range; its higher rate of fire and ability to attack multiple targets allows it to do more damage overall, defeating Crabularva in about 10 seconds.

Destroyer Mode[]

Crabularva is immune to all Gun types except Blaster. The most ideal strategy is to get near a puddle where a Crabularva is going to emerge from and start dropping and detonating Ignition Bombs in quick succession as soons as it surfaces. Once all Ignition Bombs have been used, the player should simply use the Blaster to damage them, as Grenade Bombs are slower and causing a Crabularva to be shot out of its puddle presents a moving target, making it somewhat difficult to properly take advantage of its extended vulnerability.


The following list shows how many shots it takes from each Gun and Sub-weapon type to defeat both Crabularva. Stun means Crabularva will be unable to act for a brief period of time; weapons can only stun every so often in order to prevent the boss from being stun-locked. Weak means Crabularva will take twice as much damage from the Gun than usual; in-game, they flash red, and are also stunned, when this occurs. Sub-weapons do double damage against bosses compared to enemies to mitigate their limited ammo.

  • Blaster: 200
  • Long Range: 100
  • Penetrator: 50* (stun)
  • Diffusion: 24 (weak) (farthest); 10 (weak) (closest)
  • Auto: 250
  • Reflect: 100; 40
  • Striker: 25**
  • Flame: ~45 flame+burn half-cycles
  • Wave: 200 (stun) (single shots); 68 (stun) (triple shots)
  • Grenade Bomb: [10 = 60% combined HP removed]
  • Ignition Bomb: [10 = 80% combined HP removed]
  • Turret: ~50 bullets (estimated)
  • Remote Blast: [15 rockets = 75% combined HP removed]

*Despite not causing the boss to flash red (as seen with Diffusion), Penetrator does twice as much damage as usual (it is usually on par with Long Range); this also occurs with Crabullus. These are the only two bosses where this occurs.
**As Striker can hit both targets simultaneously, it only takes 25 hits to defeat the boss, as opposed to 50.


  • Using a Grenade Bomb (or Shovel Knight's Fishing Rod) to have Crabularva completely landbound is the only way to see its full body, as it only shows its head otherwise.
  • Crabularva resembles one of the enemies in Area 2’s tank segments. They have similar body shape and also live in and hop out of toxic puddles.