The Shelbo is a purple monster that wears a giant, spiked shell, giving it the physical appearance of a monstrous snail. Although it has no visible wings, this Underworld monster is able to hover or fly through the air very fast, despite the bulky size of its shell. The Shelbo can open its mouth extremely wide to reveal a large eye, and also has the ability to create a whirlwind of suction to harm Pit by spinning very fast like a turbine. It can use this unique ability to pull the angel into deadly traps that are positioned in front of it. Even when there are no such traps in the area, the creature's body is covered in spines that can poison Pit on contact. Because the eye of the Shelbo is its only weakness, the best way to defeat this foe is to run in the opposite direction when it opens its mouth and use a backwards dash shot in order to land a hit while avoiding the suction. Otherwise, the burly shell of the creature will prevent even the strongest attacks from causing it any harm.
These creatures first appear extensively during The Reaper's Line of Sight, where they often attempt to pull Pit into the many different traps built within the Reaper Fortress. They are shown to be high-ranking members of the Underworld Army, as they are often seen guarding important doors or passageways with their large shells.
Essentially an impervious shell with lips, Shelbo fights by biting its prey. This attack reveals Shelbo's only weakness: they eye inside its mouth. Joke time: why is Shelbo good at dieting? Because it always watches what it eats. Oh!
- Its name comes from the combination of "shell" and "turbo", describing its appearance and characteristic attack.