We take visual effects in games for granted, though that's kind of the point. It's like magic tricks -- they lose their lustre once you know how they're done. That doesn't mean we don't want to know. So how about the angel wings in Diablo III? Those beautiful, wavy, incorporeal tendrils that look exactly how you'd expect?
As developer Simon Schreibt explains, the beauty is in the effect's simplicity. For example, here are all the textures used for the game's angel wings:
Add a sprinkle of shader code and you get the visuals you see in the finished product. Creative distortion of the textures allows the wings to take on different shapes and intensities, so once the base effect is done, artists appear to have a lot of control over the final look.
The video above goes through the specifics, but if you're in a reading mood, you'll find a written piece that covers the same ground below.
Diablo 3 -- Wings of Angels [Simon Schreibt]