The Shepherd Spy is a supporting antagonist of the Phineas and Ferb episode "Excaliferb". He is an unnamed shepherd who serves as a spy for the evil wizard Malifishmertz of the Malifishmertz Evil Tradesman Association.
He was voiced by Rob Paulsen, but only whispers.
When Malifishmertz hear about a group of heroes going on a journey to find the legendary sword Excaliferb, he sent a network of spies through the Tri-Kingdom Area.
One of them (the Shepherd Spy) is seen in the Inn of the Prancing Platypus, where Phineas and Ferbalot tried to recruit their friends to their journey. One of the friends known as Bufavulous the Wind Lord notices the Shepherd Spy with two sheep and informs Phineas about him, but Phineas just brushes it off before heading off with their friends.
Upon eavesdropping on this, the Shepherd Spy heads back to Malifishmertz's lair and informs him about the heroes' intentions. As Malifishmertz sends over several of his Meatlings to stop the heroes, the Shepherd Spy secretly asks him where the exit is, to which Malifishmertz responds that it is on the right and that he cannot miss it.
It is unknown what happened to the Shepherd Spy afterwards.