King Buffo is the main villain of the Courage the Cowardly Dog episode "Feast of the Bullfrogs". He is the king of the frogs.
King Buffo appeared at the Bagge's house with his frogs after the pond he lived at was dried up. The Bagge's were surprised to see all the frogs in their residence. Buffo explained to them that they will be living at their house for now on. And for them to be living there, the frogs would have to dig a hole in their living room. Muriel refused to have the frogs dig a hole in her house but Buffo ordered her to do it regardless. Eustace was fed up with all the frogs in his house and wanted to get rid of them with his mallet but Buffo's guards stopped him.
After arguing with Muriel, King Buffo ordered Courage to dig the hole which the dog began to do. When the hole was finished, King Buffo ordered Eustace to fill the hole with water but he refused. The frog slapped him with his tongue for not following his orders. King Buffo orders Muriel to get some lilypads for the pond but they came back with sponges as substitutes since they could not find any lilypads. After emptying the sponges into the pond, Buffo command Muriel and Eustace to act like frogs. They were reluctant to act as frogs but they croaked much to Courage's shock. Buffo then declared that the pond is now open to the frogs who live at the house.
King Buffo orders one of his men, Bluff, to use Courage as a tool attract flies. The frogs poured honey on him as a way to get flies which worked. Bluff brought Courage back into the house where they proceed to put the flies on Eustace and Muriel's legs. The frogs wanted to eat their legs in a feast. Seeing how dangerous that is, Courage decides to reason with the frogs but they did not want to listen. Instead, Courage created a trap for them by trapping flies on a bunch of fly paper. He placed all the fly papers on the ceiling and directed the frogs attention towards the ceiling.
After sticking their tongues out to catch the flies, the frogs were all stuck to the fly paper. Courage grabbed all of them by their tongues with the chandelier, went outside, and toss them into the distance. King Buffo realized all of this and was left shocked. Before leaving the Bagge's residence, he called Courage a "stupid dog". At the end of the episode, Buffo decides to become a baseball player.