The Big Bad Hippo

History
The Big Bad Hippo is a noted Earthbender. This guy is one of the most recognizable fighters in the Earth Rumble tournaments. For one, his extremely large size makes him hard to miss, but even more recognizable is his catch phrase "Hippo Mad!" The Big Bad Hippo's fighting style is also unique; he tosses handfuls of rocks into his mouth, chews them up, and spits them at his opponents. His signature move is called "rocking the boat," where the Hippo shifts his enormous mass from side to side, literally rocking the ring and knocking his opponent off balance. He is defeated by The Boulder in the first round. The Hippo doesn't appear to be very intelligent. Like the Boulder, he also refers to himself solely in the third person.

It's revealed in The Day of Black Sun Part 1 that the Hippo along with The Boulder are two of the people that Sokka asked his father, Hakoda to recruit for the invasion. During the Invasion, the Hippo and the Boulder proved to be very powerful Earthbenders as they took down a battlement together and another along with Toph. But in the end, the Hippo along with The Boulder is likley captured by Fire Nation forces along with the adults of the Invasion force when the Invasion failed.