Muten-Roushi

The "Turtle Immortal" is an ancient and wise martial arts master and the first Earthling to wield the Kamehameha. Though he seems frail, he is a mighty warrior. Muten-Rôshi trained Grandpa Son Gohan, Ox King, Son Goku, Kuririn, and Yamcha. His home, Kame House, a shack on a small isolated island, serves as a gathering place for the Z Fighters and friends. He is a stock character, as he is both the archetypal wise old man and dirty old man, the latter being typical of shōnen anime. Sometimes he gets cranky, which further provides comic relief. He is bald, with a thick goatee and a thick mustache. Muten-Rôshi wears beach clothes or a martial arts suit and a turtle shell on his back. He usually wields a walking stick. His companions are usually Oolong, Umigame and Lunch.

(Source: Wikipedia)