make a new image with theise settings

Press D!
and select your cutom shape tool

HAVE THEISE SETTINGS!!!

and now get out an arrow and draw it on

ok, your going to select the back part of the arrow with your rectangular marquee tool

it'll look a little like:

now go to Filter>Distort>Wave with theise settings (you dont have to use theise settings, and you can hit randomize, this is just a suggestion):

KEEP SELECTED ON THE WAVY PART OF THE ARROW
you will see that it is off the back of the none waved arrow, just do edit>free transform

,
line it up, and your done