In a sun-drenched poolside orgy, the enchanting mermaid Undyne feels a human's gaze. With a flick of her tail, she beckons him closer, her blue scales shimmering in the water. He takes her from behind, her tail undulating as he thrusts in and out, her moans echoing through the empty pool area. The water churns as he grips her tail, pulling her closer, his cock throbbing inside her. As he nears climax, he pulls out, his hot seed filling her, dripping down her tail.