Master Udon

Master Udon is a con artist who appears in the episode "Karate Island" as the main antagonist, and was voiced by the late Pat Morita. He is the owner of the Condo Island. Master Udon is also featured in the video game Fists of Foam, where he is the main antagonist who has kidnapped Sandy.

Description
Udon is a light green fish with small light yellow eyes and large, black eyebrows, a small black beard, and green lips with a black mustache. He wears an orange robe with a purple shirt and a yellow karate belt.

Role in series
Udon is the fish who calls to come to the mysterious Karate Island. He is revealed to be a con man because he captures SpongeBob and attempts to make him buy real estate. He has quite a few recruits and orders them to stop  from getting to him: The Tickler, Lip Service, and Filthy Phil.

It is revealed at the end of the episode that despite his small stature, Udon has extremely large muscles when he fights Sandy. Though quite muscular, he seems to have a low fighting capacity, as when he fights, he uses sloppy punches and forward slaps; though, he actually is able to go toe-to-toe with Sandy. Udon is defeated by her and falls out of the condo window, landing in the goo/water.

However, he is shown to have survived at the very end of the episode after SpongeBob and Sandy leave, greeting  to declare him as "King of Clarinets."

Trivia

 * Pat Morita was best known as Mitsumo "Arnold" Takahashi from the TV show ', Mr. Miyagi in ', and the Emperor of China in the Walt Disney Animation Studios 36th animated feature film, Mulan.
 * Although Pat Morita voiced Master Udon, for the most part, the line "I am Master Udon" was provided by Tom Kenny. Kenny also provides Udon's screams and grunts during his fight against Sandy.
 * Near the end of the episode, when Master Udon falls into some water, Sandy says, "You're in the soup now, Udon!" is actually named after a type of noodle soup served in Asia.
 * In the video game SpongeBob's Atlantis SquarePantis, during the SpongeBob's Director's Commentary for the level "Squidward Super Shooter!," SpongeBob mentions Sandy fighting against Master Udon. Specifically, the first exercise Sandy performed in her exercise program was traveling back to Karate Island and sparring with Master Udon.