...a mermaid!
The room behind Jamie looked to be some kind of undersea grotto lit with magical crystals; and she, herself, was a stunning vision of beauty with long, flowing hair, bright red lips, sultry eyes, and flawless skin. A pearlescent seashell bikini held fast to a buxom chest, and an elegant tail with iridescent scales flexed smoothly as she posed her legs.
Jamie staggered back onto her bed, and the reflection sat down with her, bending her tail as Jamie shuffled her legs around. She couldn't tell if this was a hallucination, or what; but to say she was afraid was an understatement. Her heavy, nervous breathing was reflected in her mermaid self taking deep breaths of the ocean. No gills could be seen in her other self, but she had other concerns besides the mechanics of mermaid respiration.
Soon enough, the image fades away; but not before her mermaid self blew a kiss to her. With a soft, feeling jolt to the heart, the mirror was back to reflecting everything as it was.