The young mermaid thrashed about as she'd been taught to.
Eventually a kindly land-dweller would try to save her. So far it'd just been the same golden-furred canine six times.
"Stop it," she scolded, even as she ruffled its floppy ears, "You're not the type of land-dweller I'm trying to drag to a watery fate."
But as the sun set, the mermaid sighed, "You'll have to do."
The dog adapted to gills and a swimming tail with surprising ease.