Crystalyd slugs are ultra rare, but they sure do come in handy for anyone who's lucky enough to win one in the Slug Run! This tunneling slug can dig through rock and earth to trap your foe, and it can also tunnel a sneaky escape when you're in a jam.
- Protoform Abilities - Can drill through soft materials.
- Tremor Tunnel - Digs an escape tunnel through any type of rock.
- Terrafirma - Hits the ground and creates a patch of churning rock and sand, dragging down foe.
- Slabsaw - Digs through a wall, creating a spinning ring of rocks used to attack foe.
- Vibroquake - Tunnels into ground, creates a sink hole to trap foe.
- The Trade (Cameo)
- The Slug Run (First appearance)
- The Thrill of the Game
- Bandoleer of Brothers
- Light as Day
- Slugterra: Ghoul from Beyond
- Slugterra: Return of the Elementals
- Slugterra: Eastern Caverns
- Get Pronto (Mentioned only)
- The Fall of the Eastern Champion (Appears in flashback(s))
- Crystalyd slugs are experts in digging.
- In A Distant Shore, a Crystalyd is shown sleeping when Eli silently goes out of the hideout.
- In Snowdance the Crystalyd that Pronto shot at Sedo returned to Eli.
- Eli has a Crystalyd named Digger.
- Eli finally used it when he escaped the Game Master's lair before it self destructed.
- During the episode "The Trade" you can see Trixie next to a cage carrying a Crystalyd.
- Crystalyds were called Tunnelers in the Slug Run.