A tale of two prawns

Once there were two prawns named Johnny and Christian. Johnny isn't quite happy. So he goes to see Cod and says, "Please can you turn me into a great big shark!" Cod waves his magic fin, and Johnny becomes a great big shark. Johnny starts eating the other prawns one by one, until one day, only Christian is left.
Johnny suddenly realises he does not want to be a shark anymore. So he asks Cod to make him a prawn again.
"Hmm," replies Cod. "I guess you've seen the error of your ways. I'll turn you back." And he waves his magic fin, and Johnny the prawn replaces Johnny the shark. Off he goes to find Christian.
"Christian, Christian, come out and play with me!" he calls.
"No, no, no, no!" Christian squeaks. "You're a great big shark and you wanna eat me!"
"No, it's OK!" Johnny calls back. "I've spoken to Cod, I'm a prawn again, Christian!"

Courtesy: Stupid-boy