The Eagle and the shepherd

Every night, a Giant Eagle swooped down and carried off one of the shepherd's sheep. The cunning shepherd tied a fleece to his back and, that night, the Giant Eagle swooped down and carried him off. At one point, the Giant Eagle shifted his grip on the shepherd. The shepherd gave an involuntary yell. "Did you say something, Sheep?" asked the Giant Eagle.

"Baa!", said the shepherd, realising for the first time that he hadn't fully thought this through.