Slug est un nom commun pour un gastéropode terrestre apparemment sans coquille mollusque. Chaque Slug à des pouvoirs spéciaux en fonction de son élément : feu, eau, terre, air ou énergie. Lorsqu'elles sont lancées avec l'aide de blasters, et qu'elles atteignent une certaine vitesse, les Slugs se transforment en une version plus grande et plus puissante d'elles-même. Quand elles sont utilisées, ceux qui les possèdent doivent se dépêcher de les recharger pour riposter. Les Slugs ont des sentiments, et si elles ont de l'affection pour quelqu'un, il se peut qu'elles fassent tout pour le (la) protéger. Elles ont besoin d'être régulièrement nourris et les bébés Slug ont besoin de soins plus spéciaux. Dans les blasters, elles sont lancés à partir d'un tuyau bleu (ou rouge) en forme de cylindr

Slug is a common name for an apparently shell-less creature which lives in Slugterra. They have special powers according to their elements, which are: Fire, Water, Air, Earth and Energy. These are the basic elements. The secondary elements are Steel, Toxic, Ice and Psychic. There are 5 Elemental Slugs which were first of their kind. They are the progenitors of all other slugs, so if one were to be corrupted, all the slugs of its lineage would suffer the same effects. So in effect, if the Air Elemental were to be ghouled, all other air slugs will become ghouls, such as Hoverbugs, Tormato, Slyren, Flatulorhinkus.... When these slugs are fired with the help of Blasters, they reach a velocity of one hundred miles per hour and transform into a stronger form called velocimorph which can be highly destructive. Once they are fired, they can only be re-used if their Slingers are fast in picking them up and reloading. Otherwise, they will return to the slinger's hideout if they are friendly to them. All Slug-Slingers have to expand their arsenal so they may use certain techniques such as communicating and using special slug collecting devices. Slugs need be fed regularly so that they remain healthy, and baby slugs need extra special care to help them mature. If experienced enough, slugs can evolve into an even stronger form called a Mega Morph. To Mega Morph a slug needs to be shot at two hundred miles per hour. If a slug is not experienced enough, it will get thrown off by the speed and the Mega Morph will fail. By using an accelerator in the blaster, a slinger can help a slug Mega Morph more easily. Slugs are kept in special cylinder-shaped cases called slug containers. The list of slugs is as follows:

Albino Boon Doc – A slug which shoots sonic rays to heal ghouls. Similar to a Boon Doc. Element: Energy

AquaBeek – A slug that can spout water and other things when transformed Element: Water

Arachnet – A purple slug that takes on a spider-like form when transformed. Can spin webs quickly to use as nets or grappling hooks. Element: Earth

Armashelt – A slug with heavy hard outer shell can roll up and bash things like rocks when transformed. Element: Earth / Steel

Blastipede – A Slug That Throws blue mines that are activated when the Blastipede's antennas touch. Element: Earth / Steel

Boon Doc – An aqua green slug with one eye. Considered to be Ultra Rare and possesses great healing powers, which can purify Ghoul Slugs. Element: Energy

Bubbaleone – A slug that can inflate itself like a balloon when transformed. It can also carry people inside its body and shoot blasts of bubbles.(A bit like soap) Element: Water

Crystalyd – A slug that can dig trenches and tunnels. Element:Earth / Steel

Diggrix – A slug that can dig and throw dirt. Element: Earth

Dirt Urchin – This slug uses spines and spikes for its attacks. Element: Earth

Enigmo – A rare slug that severely disrupts the vision of any living thing it hits, which can be reversed by being hit by the Slug again. Being hit by an Enigmo also enables the target to see auras of slugs, which makes it easier to

Fandango – A slug that can boost the energy of other nearby slugs. Element: Energy