Negative Polarity - S1.E9

Tank (Kiev) teams up with Crygen and Pyre to harness the power of a boulder of galvacite, which will make them strong enough to vanquish Metlar once and for all. However, when they storm Infernac, their enhanced magnetic powers run amuck, inducing a reversal of the core's polarity that renders Crygen and Pyre evil while changing Metlar's personality to good. The incident further initiates a chain reaction which threatens to pull Earth's deadly Van Allen belt down to the surface of the planet. Much to his own disgust, the now-altruistic Metlar brings himself to work in concert with Earth Corps to restore the natural order: they manage to reform the galvacite boulder, returning Crygen and Pyre to normal as Metlar reverts to evil and reclaims Infernac.