Mary giggles, her bovine udder jiggling in the warm water of her bathtub. She unstoppers the vial marked 'Whale', and tips it up, drinking about half of it. A warm, pleasant sensation spreads throughout her body.
Watching closely, Mary notices her lightly furred and almost white cows body begin to darken to a mix between black and blue. She settles down further into the water, her knees sticking out of the water. Soon, her entire body is a deep black-blue, except for her belly and under her arms, which has gone to a bright white.
Sitting on her cow's tail hasn't been comfortable, but now, it's getting worse! She looks between her legs, passed her now white udder, and sees her tail slowly thickening, softening, into what she knows must be her new whale tail. The end starts growing out into a fluke. Mary giggles and fondles her changing tail. It's soft, and warm. It keeps growing as other changes begin...