Primo is a fractal wolf that creates more simic (blue-green) 0/0 creatures every time you deal combat damage to a player, with those tokens getting larger the harder you swing
One took a playful swipe at a tree trunk, and its new blade cut clean through
With Nadu and Nantuko, every land drop makes more creatures, more creatures means more Nadu triggers, and more Nadu triggers means more land drops
As for the Motherlode, I think having a way to destroy nonbasic lands again and again is pretty strong and could be a valuable asset to red decks as long as youve got a reliable way to make energy counters
As an aside, couldnt Duneblast have been a more flavorful representation
But, and here's where the design adds in some deck building, the Goblin Kaboomist's toughness is exactly 2, meaning if you can enhance his toughness in any way, he can survive his own mistakes