Goon Doc are the Ghouled versions of the Boon Doc slugs. They would first appear in the episode "The Unbeatable Master, used by Dr. Blakk too kill Shanai. Later a possibly Megamorphed and unique one would appear as the main villain in the first two movies, Slugterra: Ghoul from Beyond and Slugterra: Return of the Elementals, but with powers of no other slug.
- Protoform Abilities
- Makes people feel ill when standing nearby
- for more see "The Goon"
- Medusi - A poison attack that will slow an opponent down for a short period of time.
- 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.
- Leachfang - A poisonous bite drains the opponent of their health and worsens internal ailments.
- 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 a Blakk Industries manufactured Goon Doc that resides in Slugterra, while the other is from The Eastern Caverns (referred to as "The Goon").
- Even though the Goon Doc slug is in fact a ghouled version of a Boon Doc slug, the popular slug "Doc", as is found in Return of the Elementals is the Energy Elemental. It left some people questioning what a Boon Doc/Goon Doc slug is if "Doc" is the Energy Elemental?