Rhyhorn

Rhyhorn's massive bones are 1,000 times harder than human bones. In "Showdown at Dark City," Ash and friends are trapped in the middle of a Pokemon gang war between the rival Yas and Kaz Pokemon Gyms. The unlicensed gym trainers use their Pokemon for personal battles. During a huge battle, the gym leaders let loose several Pokemon, including a monstrous Rhyhorn who runs rampant through the town, trying defeat the other gym's Pokemon.

First appearance: Episode 42—"Showdown at Dark City"