'Sergeant "Sparky" Pryor' is the (mostly) face- and voiceless person on the other end of the 4077th's phone line. Usually Radar or Klinger would call him, if they need something or want some kind of (probably underhand) fix or favor for an unusual situation. In other episodes, Sparky is neither heard nor seen, but the 4077th staff invariably need him for some favor or other.