The Tamaugachi is a dangerous creature that inhabits the 4th Layer of The Abyss. It resembles a large porcupine with a head that looks like a mask with multiple holes. It is herbivorous and eats algae that grow at dairakazura, however, it is ferociously temperamental and defensive over his territory. Although the Kenzan Kazura is an important passage route for Delvers, the Tamaugachi considers the entire 1 km diameter of it to be its territory. Delvers need to be exceedingly cautious and pray for a safe passage when in the area. A single one has taken the limbs and/or lives of over 100 black whistle Delvers.
As dangerous as it is, it is seemingly a very rare creature, since only a single one was spotted on the fourth layer. If its life is threatened, it will shed its needles to use it as a bait to escape. Their needles have a slow growth rate, so their scarcity might be due to the fact that not many get to a fully matured state.
It is covered with long sharpened needles that can pierce through metal like paper, and they're laced with a deadly poison. While the Tamaugachi's poison is quite slow at killing its victim, it is extremely effective, greatly weakening those affected by it and expanding quickly, which is why many Delvers resort to amputating their limbs.
They are able to instantly unleash a fearsome amount of strength at any given moment, even on wet ground. Its most impressive trait is their ability to sense the forcefield of the abyss, which is very uncommon for creatures of the 4th layer. This grants them the ability to sense the flows of consciousness and results in a foresight-like instinct that allows them to predict every movement of other living beings. This makes it almost impossible to emerge victorious on a battle against it, and because of its ability to deal fatal wounds to any wildlife with its poison, it is said that there no longer exists a creature within the fourth layer that can be called its equal. It has one major weak point, however. The five holes on his face are its force field sensing organ, and it's an extremely sensitive spot. If hit or touched there, the Tamaugachi will be thrown into an inconceivable pain and a state of confusion that makes it go berserk. However, since it can read one's movements, it is likely that one would never be able to touch it. White Whistle Delvers are likely the only humans capable of defeating one in combat.
- It was originally an animal called "Tokajishi" but because it messes up treasures (Tama) and lives (Tamashi), Delvers started calling it "Tamaugachi" instead.
- In the English Sub, the Tamaugachi is referred to as the "Orb Piercer"