Sandayu Dokumamushi (毒蝮三太夫 Dokumamushi Sandayuu), real name Iyoshi Ishii (石井伊吉 Ishii Iyoshi), is a Japanese actor. He portrayed Daisuke Arashi in Ultraman and Shigeru Furuhashi in Ultraseven. He has been a radio personality on the Tokyo Broadcasting System (TBS) since October 6, 1969. His radio program is famous for vulgar language and is popular with an older audience. He is nicknamed Mamu-chan (まむちゃん Mamu-chan), Viper/Mamushi (まむし Mamushi), and Mr. Viper/Mamushi-san ( まむしさんMamushi-san ).
- Ultraman: Daisuke Arashi
- Ultraseven: Shigeru Furuhashi
- Heisei Ultraseven: Captain Furuhashi (1994 TV Specials), TDF Staff Furuhashi (1998 -1999 OV)
- Ultraman Max: Security Guard (credited as Old Man) (Guest Appearance, Episode 33)