How do I make a sprite turn around the X or Y axis?

I have a sprite, how do I make effect to make it turn around the X or Y axis?

You mean like flipping in 3D?

You can decrease its width to 0, then mirror it and increase the width back. But it won't look very nice, because C2 can't skew sprites.

If you want a nicer effect, you should either make a frame-by-frame animation or use some plugin.