A scorpion was walking along the bank of a river, wondering how to get to the other side. Suddenly, he saw a fox. He asked the fox to take him on his back across the river.
The fox said, "No. If I do that, you'll sting me, and I'll drown."
The scorpion assured him, "If I do that, we'll both drown."
The fox thought about it and finally agreed. So the scorpion climbed up on his back, and the fox began to swim. But halfway across the river, the scorpion stung him. As poison filled his veins, the fox turned to the scorpion and said, "Why did you do that? Now you'll drown, too."
"I couldn't help it," said the scorpion. "It's my nature."