Stalagmite 17 is the most highly maximum security prison in SlugTerra.
Stalagmite 17 first appeared in "Mission: Improbable", where Mr. Saturday took over and zombified the staff. After a fusion shot failed, Mr. Saturday captured and placed the Shane Gang in Stalagmite 17. Eventually this caused Burpy and Pronto to come and break the gang out, lifting the effects of the Cryptogrif Slug on the way.
List of Inmates
- Mr. Saturday
- The Shane Gang (formerly)
- Dr. Blakk (formerly)
- Mission: Improbable (First appearance)
- Back to Blakk
- Dark as Night (Appears in flashback(s))
- Slugterra: Ghoul from Beyond (Appears in flashback(s))
- Stalagmite 17 may be based off of Alcatraz prison.
- In Mission: Improbable, Trixie gets electrocuted when she tries to escape through the ventilation duct. This is a detail taken from the only successful escape from Alcatraz prison when 3 inmates successfully escaped through the ventilation duct in June 1962.