I'm just a scorpion

The Scorpion and the Frog

One day, the scorpion wanted to get across the river, but he couldn't swim. So he found someone who could....
"Hellooo Mr. Frog! Would you be so kind as to give me a ride on your back across the river?"
"Well now, Mr. Scorpion! How do I know that if I try to help you, you wont try to kill me?" asked the frog hesitantly.
"Because," the scorpion replied, "If I try to kill you, then I would die too, for you see I cannot swim!"
Now this seemed to make sense to the frog, So the frog agreed to take the scorpion across the river.  The scorpion crawled onto the frog's back.
Halfway across the river, the frog suddenly felt a sharp sting in his back and, out of the corner of his eye, saw the scorpion remove his stinger from the frog's back. A deadening numbness began to creep into his limbs.
"You fool!" croaked the frog, "Now we shall both die! Why on earth did you do that?"
The scorpion shrugged. "I could not help myself. It is my nature. I am just a scorpion."