How would I create this background effect?

Question

What would you call the effect applied to the backgrounds in the Giygas fight of Earthbound, and the battle backgrounds in Mother 3? This is what I'm talking about.

http://www.youtube.com/watch?v=tcaErqaoWek

http://www.youtube.com/watch?v=ubVnmeTRqhg

Now anyone know how I could go about this without using animated images, or using openGL?

Answer 1

These are also called demo effects. They are used on demoscene events, beside games.

Check out this effect collection.

Answer 2

it's just a textured quad, with sin and cos applied to the texture coordinates