A Gronk is a mammalian creature native to Eternia. It vaguely resembles a duck-billed platypus with white fur and spines on its back, a pink tuft of fur on its head, short pink legs, and two toes on each of its large feet. It moves about by hopping.
Orko once performed an experiment that transferred his magic into a Gronk and sent it to the distant world of Omiros. The Gronk fell into the hands of an evil wizard named Zalt, and Orko had to travel to Omiros with He-Man and Battle Cat to retrieve it.