I love the story of Tiddalik, I have a childrens book called 'The frog who wouldn't laugh' by Cecilia Egan and illustrated by Elizabeth Ager. It is a version of the story for children though isn't an exact version and doesn't have where it is derived from in the book. But this is the story:

'The frog who wouldn't laugh' by Cecilia Egan and illustrated by Elizabeth Ager.
"Tiddalik was a giant frog. He was not just big, he was enormous! He was the largest frog ever known- his bulging eyes looked out over the tree tops: over the hill tops and even over some low clouds.
Tidalik was as big as a mountain.
One morning Tiddalik woke up feeling thirsty. In fact he was not just thirsty, he was enormously, gigantically, terribly thirsty.
He drank a puddle, the drank a billabong, then a lake then a river and -oh dear! Tiddalik drank up all of the fresh water in the world.
There was nothing left for the other animals to drink and no water for the trees and plants. All the animals and plants started dying. If they didn't get some water soo, Tiddalik would be the only creature left alive in the world!
"Tiddalik, please open your mouth and let out the water for us!" they begged. But Tiddalik swollen up with water, just sat there with his mouth shut and did not even open it to reply.
The animals did not know what to do. They could not think of any way to make the great big fat frog let out the water they needed so desperately, until a wise old wombat said "If we could just make him laugh, Tiddalik would open his mouth!"
So all of the animals tried to make Tiddalik laugh.
The Kangaroo jumped over the emu, the lizard waddled around on his hind legs with his stomach sticking out and the kookaburra told his funniest stories, which were so funny that the other animals rolled about laughing!
They lyre bird even ticked Tiddalik witha feather. But it was no use. THe great big frog just sat there staring. He didn't even smile!
"It's nou use", said the animals sadly, "Nothing will make him laugh."
Just then the eel began to dance. He started witha slow, dignified movement, but danced faster and faster until he was wriggling and twisting himsefl into the funniest and strangest shapes, tying himself into knots!
And Tiddalik began to shake . He shook harder and harder as if a great big laugh was beginning somewhere in his tummy. It rumbled up and up and all at once Tiddalik's mouth opened and a huge laugh roared out!
With that, all of the water he had drunk gushed out like a fountain and flowed away to fillup the lakes, swamps, riverbeds and billabongs.
The animals all danced for joy, and congratulated the eel for being the only one who could make Tiddalik laugh!"

Woah that was longer than I thought....but I love the story!! Hope you did too, if you got this far!