The Friendly Wolf

A wolf was standing behind a herd of sheep. The shepherd had doubts about the wolf and kept a close eye on the sheep. On the next occasion, the wolf stood silently with the sheep again and did not attack them. Slowly, the wolf became part of the herd. The shepherd believed the wolf would never harm the sheep.

One day, the shepherd decided to go to the city for work. Before going, he entrusted the wolf with guarding the sheep. Just as the shepherd left for the city, the wolf attacked the sheep one by one and killed them all. When the shepherd returned and saw what had happened, he realized his folly. 

A wolf as a friend is worse than an enemy.