Samus Aran encounters two free-roaming Imago larvae before the main Kiru Giru battle. They have vulnerable undersides, which Samus can damage either by shooting through the ceiling with the Wave Beam or planting Bombs in their path (using Missiles to push them back, making the battle similar to Crocomire from Super Metroid). After killing these two Imago Larvae, Samus sees a third one before she fights Kiru Giru; however, this one appears to have died long ago and is pierced by Tangle Vines, which seem to be consuming the larva's body from within.
Though not directly expressed, this boss battle consists of saving the larva that is ensnared and slowly being devoured by Tangle Vines. Samus witnesses many other Tangle Vines consuming creatures and covering entire rooms before entering this chamber. To defeat it, Samus must freeze a Winged Ripper flying about the room, jump on it, and shoot the vines that are holding the larva with Missiles, however, it is possible to defeat it without using the Ripper by jumping up and shooting diagonally. Spores are constantly launched from the larva, either as a result of interior decay caused by vines or the latter attempting to reproduce. As Samus destroys the vines, the larva slowly changes from grey to its natural colors (possibly because the vines were absorbing its blood). When defeated, the larva itself will fall through the floor where it later forms a cocoon and grows into an adult Imago. An interesting thing to note is that the winged Ripper can be killed if it is directly underneath the Larva the moment it falls, thus crushing it.
On the official Japanese website for Zero Mission, the Kiru Giru (in all its forms) are referred to as a Giant Evolving Bug.
- The first two Kiru Giru larvae can be killed simultaneously with a single Power Bomb, if Samus encounters the creatures after exploring Chozodia. Likewise, they can also be defeated with a single beam shot to their underbellies after acquiring the Plasma Beam.
- The room containing Kiru Giru also contains the only visible quantities of water in Norfair featured in Zero Mission, although if Samus returns after defeating Ridley, the pools will have dried up. Some rooms in Norfair featured in Super Metroid have water, specifically in the caverns after Crocomire.
- This miniboss seems to pay tribute to Spore Spawn, as the former has a slightly altered version of the latter's theme and both can attack by launching spores.
- The mechanic of firing at the Kiru Giru Larva to push them back is similar to the battle with Crocomire, the Omega Metroid in Metroid Fusion and the Desbrachians. Coincidentally, Crocomire was dropped from Zero Mission.
|Food, Nourishment and Sustenance|
|Plants||Blueroot Tree • Fruit • Red Starburst • Sap Sac|
|Species||Geruta • Embers • Kiru Giru • Pirate Militia • Reo • Ripper • Sciser • Scritter • Skree • Space Pirate • Tallon Crab • Torizo • X Parasite • Zoomer|
|Specific Humans||Samus Aran • Virginia Aran|
|Carrion||"Deceased Soldier" • Amok Mommy|
|Liquid||Lava • Phazon|
|Artificial/Misc.||Elite Nutrient Mix • Energy • Nutrient-grade biomatter • Synthetic Metroid rations • Wrecked Ship|
|Bosses in the Metroid series|
|Metroid||Kraid • Ridley • Mother Brain|
|Metroid: Zero Mission|| King Worm • Mua • Kraid • Kiru Giru • Imago • Ridley • Mother Brain • Ruins Test • Ridley Robot |
|Metroid II: Return of Samus||Alpha Metroid • Arachnus • Gamma Metroid • Zeta Metroid • Omega Metroid • Queen Metroid|
|Super Metroid||Torizo • Spore Spawn • Kraid • Crocomire • Phantoon • Botwoon • Draygon • Golden Torizo • Ridley • Big Metroid • Mother Brain|
|Metroid: Other M||Brug Mass • Fune and Namihe • Groganch • King Kihunter • Mystery Creature • Goyagma • RB176 Ferrocrusher • Rhedogian • Vorash • Ridley • Nightmare • Queen Metroid • MB • Phantoon|
|Metroid Fusion||Arachnus-X • Elephant Bird • Zazabi • Serris • B.O.X. Security Robot • Mega Core-X • Scientist • Yakuza • Nettori • Nightmare • Neo-Ridley • SA-X • Omega Metroid|
|See also: Bosses in Metroid Prime Series|