Una observed Charlie. Obviously the blond young man truly loved water, even when it was cold and rushing around him. Una smiled at that. Yes, here was a boy who was very much at ease in this element. Water WAS his element, obviously. This gave Una a lot of ideas. A lot of mischievous little ideas. Transforming this boy was a clear thing to do, but into what? Something water related but why exactly? The options were extremely large. But when seeing that Charlie admired and stretched his own muscles and body, Una could see that this human boy was a bit of a braggart. He loved himself and clearly he was quite confident with mortal ladies. This body created through hours of swimming could not leave mortal ladies indifferent. Well, maybe he could get used to living without that charisma but keeping his swimmer body to still have fun. Una therefore threw her spell at Charlie, transforming him into a gillman. He would keep his passion for the element of water. Indeed, it would actually be intensified. Shouldn't he feel lucky?
"What the...?" uttered Charlie, feeling weird because of the magic hitting him.
But the changes were instantaneous. Gills split and erupted on his neck, and he clutched his neck, in pain and drowning his own cries of terror. But his hands widened and became webbed. His nails became claws. His nose retracted into his face, his penis and testicles into his groin and his skin covered himself in scales. His teeth were now pointy and his face that of a fish. Even his coccyx hurt like crazy because of a tiny tail coming out of his spine, elongating it. Charlie then fell into the water, encumbered by his feet, that had become so long, large and webbed. Keeping his balance on land was as easy as wearing humongous flippers! The water felt unbelievably soothing to him though and he realized he could actually breathe under it!
Meanwhile, Una was watching, most satisfied with her feat. Full of pride, she pondered if Puck was as successful as she was with that other human boy.