An 1847 illustration of “The Scorpion and the Turtle” from the Persian Kalilah and Dimna, an ancient fable which might have inspired The Scorpion and the Frog.

Wikipedia Entry

The Scorpion and the Frog

  A scorpion and a frog meet on the bank of a stream and the 
scorpion asks the frog to carry him across on its back. The 
frog asks, "How do I know you won't sting me?" The scorpion 
says, "Because if I do, I will die too."

  The frog is satisfied, and they set out, but in midstream,
the scorpion stings the frog. The frog feels the onset of 
paralysis and starts to sink, knowing they both will drown, but has just enough time to gasp "Why?" 

		Replies the scorpion: "Its my nature..."