What is the name of Jaraiya and Naruto's strongest toad?

Gamabunta (Japanese: Fat Toad) is the Toad King. Equal in power to Manda (King of Snakes). He's the largest toad Jiriya or Naruto ever summon.

Naruto summons this toad for the first time during his very first training with Jiriya, Jiriya throws him off a cliff (WTF?!) and using the Kyuubi's power, he summons Gamabunta.

The Fourth Hokage was the only one Gamabunta listened and obeyed perfectly.