It's Story Time!! with Weener and PooPoo

One day, Weener and PooPoo were walking along the causeway when all of a sudden, a giant merman leapt out of the water. He said "Hello, Weener and PooPoo. How would you like to have an underwater adventure today?" Weener and PooPoo said that they'd like to have an underwater adventure very much, but they couldn't breathe underwater. "That's too bad," said the giant merman, and he dived back into the water.

"I really wish I could have gone on an underwater adventure with that giant merman," said Weener.
"Me too," said PooPoo. "But we can't breathe underwater."
"I know," said Weener. "But maybe we could grow gills."
"How are we going to grow gills?" asked PooPoo.
"I still have some fairy dust left from our last adventure," replied Weener. "Maybe if I fling it into the air, a fairy will appear and give us gills!"
"That sounds like a great idea!" said PooPoo.
Weener pulled the last of the fairy dust out of his pocket, and flung it into the air. Weener and PooPoo held the breath.
After a couple of seconds, the wind started to pick up. They thought they heard faint music. Then with a loud POP! a fairy appeared before them.
"Hello," said the fairy.
"Hello!" said Weener and PooPoo. "We were wondering if you could give us some gills so that we could have an underwater adventure with the merman."
"Sure," said the fairy. "But be careful. Sometimes mermen can be tricky."
"What do you mean, tricky?" asked PooPoo.
"Well," said the fairy, "he might try to steal your soul and put it in a bottle and then drink it for breakfast! But he probably won't."
"Well in that case, we have nothing to worry about!" said Weener.
"Ok," said the fairy, and with a wave of his arms, he gave Weener and PooPoo gills. Then with a CRACK! he disappeared.

Weener and PooPoo stared wide-eyed at each other. They clapped their hands to their necks. They had gills!
"I can't breathe," Weener mouthed to PooPoo.
"What?" PooPoo mouthed back. He gestured at the water. Weener nodded, and they both jumped in.

Under the water, everything looked blue. Not surprising, thought Weener. The merman was nowhere in sight. Weener and PooPoo started swimming away from the causeway, and down, down.
Seaweed tickled their legs, and tiny fish swam around them, but still there was no sign of the merman. Weener tried to ask one of the bigger fish if they had seen the merman, but the fish ignored him. "How rude!" said Weener. PooPoo acquiesced.