Tortoise Matsumoto (トータス松本 Tōtasu Matsumoto, born December 28, 1966 as 松本敦 Atsushi Matsumoto) is the lead singer of the Japanese guitar group, Ulfuls. He has also had a couple of acting roles in TV dramas, starting with Namida o Fuite (涙をふいて) in 2000.
Trigun character Nicholas D. Wolfwood is modeled after him.
On July 11, 2018, Matsumoto, Tamio Okuda, Kazuyoshi Saito, Yohito Teraoka (Jun Sky Walkers), Takashi Hamazaki (Flying Kids) and Yo-King (Magokoro Brothers) announced the formation of a supergroup called the Curling Sitones (カーリングシトーンズ, Kāringu Shitōnzu). Each member is a multi-instrumentalist with all of them at-least being able to provide vocals and guitar and, like the Traveling Wilburys, each uses a pseudonym featuring "Sitone". They formed for a concert on September 23, 2018 at Zepp Tokyo celebrating Teraoka's 25th anniversary as a musician.