Bomb Guardian

The Bomb Guardian retains many of the characteristics of the Alpha Sandigger. However, it is generally darker in coloration and has only one head, the other being replaced by a glowing tail stump. Furthermore, it has barbs all over its body, as well as a crest of barbs along the back of its head. Its mandibles are larger and barbed.

Battle

As Samus steps into the arena, the doors close, and an Alpha Sandigger appears. When the Ing that has stolen Samus's Morph Ball Bombs possesses the Alpha Sandigger, it transforms into the first Sub-Guardian boss that Samus fights: the Bomb Guardian. In the process, one of the creature's heads becomes a Bomb-producing tail.

The Bomb Guardian slithers along the ground, dropping Bombs out of its tail at a steady rate. It will occasionally raise its head and spray several Bombs into the arena from its mouth. If Samus is too far away, the Bomb Guardian will perform a fast moving charge in order to close in on her. The tail can be attacked to stun the creature, at which point the Bomb Guardian shrieks and lifts up its head. The head then becomes vulnerable for a short time. If Samus does not inflict enough damage to make the creature flinch (one Charge Beam shot will suffice), it will spray a great number of Bombs into the air, which will fall and scatter over the battlefield. If Samus manages to inflict enough damage, the whole cycle is repeated until the Bomb Guardian dies, earning Samus the Morph Ball Bomb upgrade that was stolen from her earlier in the game.

Official data

Logbook entry

Development notes

Within the Metroid Prime 2: Echoes Bonus Disc resides an unused Logbook entry for the Bomb Guardian. In it, the Bomb Guardian is called the Bombdigger. Because "Alpha" creatures (besides the Dark Alpha Splinter) have not yet been added, it is possible the Bomb Guardian was spawned from a normal Sandigger.

Trivia

• If Samus enters Morph Ball mode at any time during the battle and the Bomb Guardian is near, the creature will pick up Samus with its jaws and then throw her aside. Normal Sandiggers will also do this.
• Normal Sandiggers and the Alpha Sandigger have light-colored body segments with darker tissue in between. These colors seem to have switched for the Bomb Guardian, which is mostly dark, with light blue tissue in between body segments.
• The Bomb Guardian is perhaps the weakest of the Sub-Guardian bosses, as a single charged shot can deplete nearly a third of the creature's health.
• The Bomb Guardian shares its battle theme, Short Battle, with numerous other Darkling creatures in the game.
• The multi-Bomb attack references the Five-Bomb Drop technique from Super Metroid, and the later Metroid: Other M.
• By Sequence Breaking and equipping Samus with the Light Beam, Dark Beam, and Annihilator Beam during this boss battle, the Bomb Guardian is revealed, strangely, to be invulnerable to all three weapons. The reason for this is most likely because it was not scripted to encounter any of these weapon. 
  • However, any Charge Beam shot can still stun the creature and, when stunned, can also receive damage from said charged shot. Firing an Entangler shot will freeze the creature, and when its head is vulnerable, firing a Lightblast shot may potentially burn the creature. Similarly, when the Bomb Guardian is stunned, all four Charge Combos can instantly kill this creature.
  • By hacking, it appears the Bomb Guardian can be damaged by the Screw Attack and the Boost Ball; both must be used on the creature's head to damage it. A Power Bomb will instantly kill this creature. Strangely, Morph Ball Bombs can both stun and damage the Bomb Guardian.
  • As long as the Morph Ball Bomb is not acquired (either before or after the Bomb Guardian's death), every time the room is "reloaded", the boss fight will also reload (the Bomb Guardian will disappear once the Morph Ball Bomb upgrade is acquired.) If this boss fight is triggered after visiting the Agon Energy Controller, then the War Wasps in the Agon Temple will also appear during the fight (including during cutscenes).
• The Bomb Guardian's ability to launch energy Bombs, along with its wormlike characteristics, is shared greatly with the Fune and Namihe boss duo in Metroid: Other M.
• The Bomb Guardian resembles the Charge Beam Beast from Metroid: Zero Mission in body shape and head.
• A large Sandigger that may be the Bomb Guardian appears in Metroid Prime: Episode of Aether. This massive Sandigger ambushes Bravo Team after they assume they have destroyed all the attacking Sandiggers, and is quickly destroyed by Samus.

Gallery

The Sandigger is possessed

Samus engages the Bomb Guardian

The Guardian explodes, killing the Ing in control of it as well.

Frozen by the Dark Beam (via Sequence Breaking). It can be frozen if a direct Entangler shot strikes its head or tail.

Samus damages its head with enough force.

Concept art

Possible appearance in Episode of Aether.