The Hard Part Slugterra : Season 2 Episode 12

Eli and Kord have been trying to create a fusion shot: two slugs shot at exactly the same time that can merge their powers! But they'll need to mod Eli's blaster to handle it. In search of the one missing part that will complete Eli's Double Barreled Blaster, the gang journey to the Scrap Heap, a junk yard cavern of epic proportions. Finding the part isn't easy. Getting out with it alive past Boss Ember and his Scrap Force is nearly impossible.