Slugterra is an underground sci-fi adventure where "the ammo's alive." 15-year-old Eli Shane follows in his father’s footsteps to become a Slugslinger, using powerful slugs that transform into magical beasts when fired at high speeds.
The first season introduces Eli, his mentor-slug Burpy, and his crew: Trixie, Kord, and Pronto. Slugterra (TV Series 2012–2016) - Plot - IMDb slugterra episode guide
Here is a list of the episodes: