Once actively exposed to a moon stone, Nidorino transforms into Nidoking. It's now bipedal, has longer limbs, monstrous size, and thick armor-like plates across its body with its signature spines. It still retains its violet and green color palette but adds a silvery grey into the mix.

After transforming, its power has increased by a lot. While its armor can defend against powerful attacks, it's noted to be proud of its strength. It can break bones with a strike of its tail, its horn is so hard that it can pierce diamonds, and it can inject a debilitating venom from it too.