Creator: Double Dutchess
Apparently, 21 June is National Sea Shell Day in the USA. I can't tell you exactly how I got from there to Spike being a merman, but here he is. Buffy is there too, of course.
Full-size wallpaper HERE (1920x1080).
Credits: merman | wedding dress | wave photo by Dimitris Vetsikas | shell photo by Miriam Blada
The underwater photo I used for the bottom of the wallpaper, I stole from here.