- Protoform Abilities
- Makes people feel ill when standing nearby
- for more see "The Goon"
- Medusi aka Leachfang - A poison attack that will slow an opponent down for a short period of time. It drains their health and worsens internal ailments.
- Creepsleep - Poison paralysis drops opponent into a temporary coma.
- Turncloak - Emits a ball of dark light that induces a zombie-like feral state. Slingers will begin to attack allies.
- Ghoulgoyle - Hits an opposing slug and uses dark energy to transform them into a ghoul.
- Darkcloak (unofficial name) - see "The Goon"
- The Unbeatable Master (First appearance)
- Slugterra: Ghoul from Beyond
- Slugterra: Return of the Elementals
- Slugterra: Eastern Caverns (Appears in flashback(s))
- Second Chances (Cameo)
- The Fall of the Eastern Champion (Appears in flashback(s))
- A total of two Goon Docs have been seen in the series; One being in the possession of Dr. Blakk in the 99 Caverns and the other being "The Goon" a Goon Doc orginally from the Eastern Caverns. Blakk's Goon is presumed cured offscreen by Doc, after his defeat in "Light as Day".