A scorpian on the banks of the river wants to cross but could not swim.
The scorpian asks a nearby frog if the frog would give the scorpian a ride on his back to cross the river.
The frog replies "...Oh, no! For you are a scorpian and you will sting me with your poisonous tail and kill me".
The scorpian replies "...but I really need to cross this river. I promise I will not sting you".
With this assurance, the frog allows the scorpian on his back as he wades into the river.
Halfway across the river, the scorpian stings the frog with his poisonous tail.
The startled frog cries out to the scorpian "Why have you stung me when you promised not to? Now I will die and we will BOTH surely drown"
The scorpian replies "What can I say, I AM a scorpian afterall".