The Monkey king is the ruler of the planet where Blasternaut, GC and Spot have crash landed. The old mystic told the Blasterpals that their wish to escape can be granted by presenting him with the "medallion of prosperity" along with a backstory that 5 fragments of the medallion were scattered all over the kingdom plaguing the land with Chaos.
Eventually the Blasterpals succeeded in delivering the medallion of prosperity to the monkey king who offered them the Monkey ship (Despite not being Federation Standard GC is satisfied). But to leave the planet the Monkey king wants the Blasterpals to leave Spot behind, while GC and Blasternaut discovered his motive that the humming noise from the superconductor which is the source of the monkey king's power which needs a metal object (in which case Spot showcased in the opening segment when the crash shorted out his anti-electromagnetic Mechanism) that can be drawn to it's electromagnetic field.
Blasternaut bowls Spot to the superconductor which destroys the Monkey king's appearance, Exposing the all that's left is a small monkey in ornate robes, who is an attention seeking fan of the Blasterpals. Blasternaut, GC and Spot all wanted to arrest him but The Monkey king atones and reforms for his treachery inflicted on the Blasterpals quest, by helping them get back to Galactic Base (With Spot included). He is Last seen waving goodbye to the Blasterpals who were taking off on the Monkey Ship. ("Math Blaster ages 9-12")